The authors thank the Nikon Imaging Center at Istituto Italiano di Tecnologia, Genova, Italy (NIC@IIT).

<ol>
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M., Zvonok, N., Whitten, K. M., Wood, J. T., Makriyannis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+spectrometric+characterization+of+human+N-acylethanolamine-hydrolyzing+acid+amidase.">Mass spectrometric characterization of human N-acylethanolamine-hydrolyzing acid amidase.</a> J Proteome Res. 11, 972-981 (2012).</li><li>Bandiera, T., Ponzano, S., Piomelli, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+the+discovery+of+N-acylethanolamine+acid+amidase+inhibitors.">Advances in the discovery of N-acylethanolamine acid amidase inhibitors.</a> Pharmacol Res. 86, 11-17 (2014).</li><li>Sasso, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antinociceptive+effects+of+the+N-acylethanolamine+acid+amidase+inhibitor+ARN077+in+rodent+pain+models.">Antinociceptive effects of the N-acylethanolamine acid amidase inhibitor ARN077 in rodent pain models.</a> Pain. 154, 350-360 (2013).</li><li>Duranti, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-(2-oxo-3-oxetanyl)carbamic+acid+esters+as+N-acylethanolamine+acid+amidase+inhibitors:+synthesis+and+structure-activity+and+structure-property+relationships.">N-(2-oxo-3-oxetanyl)carbamic acid esters as N-acylethanolamine acid amidase inhibitors: synthesis and structure-activity and structure-property relationships.</a> J Med Chem. 55, 4824-4836 (2012).</li><li>Ponzano, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+structure-activity+relationship+(SAR)+of+2-methyl-4-oxo-3-oxetanylcarbamic+acid+esters,+a+class+of+potent+N-acylethanolamine+acid+amidase+(NAAA)+inhibitors.">Synthesis and structure-activity relationship (SAR) of 2-methyl-4-oxo-3-oxetanylcarbamic acid esters, a class of potent N-acylethanolamine acid amidase (NAAA) inhibitors.</a> J Med Chem. 56, 6917-6934 (2013).</li><li>Solorzano, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+structure-activity+relationships+of+N-(2-oxo-3-oxetanyl)amides+as+N-acylethanolamine-hydrolyzing+acid+amidase+inhibitors.">Synthesis and structure-activity relationships of N-(2-oxo-3-oxetanyl)amides as N-acylethanolamine-hydrolyzing acid amidase inhibitors.</a> J Med Chem. 53, 5770-5781 (2010).</li><li>Vitale, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+structure-activity,+and+structure-stability+relationships+of+2-substituted-N-(4-oxo-3-oxetanyl)+N-acylethanolamine+acid+amidase+(NAAA)+inhibitors.">Synthesis, structure-activity, and structure-stability relationships of 2-substituted-N-(4-oxo-3-oxetanyl) N-acylethanolamine acid amidase (NAAA) inhibitors.</a> ChemMedChem 9. 9, 323-336 (2014).</li><li>Fiasella, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3-Aminoazetidin-2-one+derivatives+as+N-acylethanolamine+acid+amidase+(NAAA)+inhibitors+suitable+for+systemic+administration.">3-Aminoazetidin-2-one derivatives as N-acylethanolamine acid amidase (NAAA) inhibitors suitable for systemic administration.</a> ChemMedChem 9. 9, 1602-1614 (2014).</li><li>Armirotti, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=beta-Lactones+Inhibit+N-acylethanolamine+Acid+Amidase+by+S-Acylation+of+the+Catalytic+N-Terminal+Cysteine.">beta-Lactones Inhibit N-acylethanolamine Acid Amidase by S-Acylation of the Catalytic N-Terminal Cysteine.</a> ACS Med Chem Lett. 3, 422-426 (2012).</li><li>Nuzzi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potent+alpha-amino-beta-lactam+carbamic+acid+ester+as+NAAA+inhibitors.+Synthesis+and+structure-activity+relationship+(SAR)+studies.">Potent alpha-amino-beta-lactam carbamic acid ester as NAAA inhibitors. Synthesis and structure-activity relationship (SAR) studies.</a> Eur J Med Chem. 111, 138-159 (2016).</li><li>Bonezzi, F. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Important+Role+for+N-Acylethanolamine+Acid+Amidase+in+the+Complete+Freund's+Adjuvant+Rat+Model+of+Arthritis.">An Important Role for N-Acylethanolamine Acid Amidase in the Complete Freund's Adjuvant Rat Model of Arthritis.</a> J Pharmacol Exp Ther. 356, 656-663 (2016).</li><li>Smith, P. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+protein+using+bicinchoninic+acid.">Measurement of protein using bicinchoninic acid.</a> Anal Biochem. 150, 76-85 (1985).</li><li>Speers, A. E., Cravatt, B. 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The authors have nothing to disclose.

Enzyme activity is finely regulated at different levels, including RNA transcription, protein synthesis, protein translocation, post-translational modification, and protein-protein interaction. Often, enzyme expression alone does not account for its activity. ABPP was developed to study the activity of proteins in their native state. Two features are required: a chemical probe that covalently binds to the active site of an enzyme of interest and a reporter tag to detect the probe-labeled enzyme.
Probe design and synthesis are critical points of the procedure. The probe must have adequate affinity and selectivity for its target. Moreover, the presence of a reporter tag must not affect target engagement. This issue is largely overcome by the design of a two-step ABP, in which the reporter tag is introduced after the target has been caught. Tag-free probes are particularly suitable for in vivo studies, in which protein activity can be evaluated in a living cell or organism, with minimal external alteration. The NAAA probe ARN14686 was designed to fulfill the requirements outlined above. The &#946;-lactam reactive warhead was chosen based on prior results obtained with the &#946;-lactam class of NAAA inhibitors16,26. These compounds inhibit NAAA in a potent and selective manner by covalently binding to the catalytic cysteine of the enzyme. Moreover, the compounds were shown to be systemically active16. We introduced a C9 saturated aliphatic chain, taking into account the increased affinity of NAAA for long aliphatic chains. A terminal alkyne was added to allow for two-step labeling.
Another critical step is selecting the dose and the time for in vivo administration. This depends on the stability of the probe in plasma, its target affinity, and its selectivity. The correct dose must be selected to allow for target capture while avoiding engagement of possible off-targets. We found that 3 mg/kg ARN14686 i.v. was optimal to capture NAAA selectively. Higher doses resulted in the capture of the homologous cysteine amidase, acid ceramidase. With regard to treatment length, when analyzing well-perfused organs, like lungs, a short time (2 hr) may be sufficient to allow for the probe to react with the target. For paws, however, we were obliged to double the reaction time.
A possible issue in target analysis by protein blot is due to the presence of naturally biotinylated proteins. These will inevitably be identified together with specific probe targets. We found that introducing a preclearing step with streptavidin beads before performing CC greatly increased the quality of our results. On the other hand, the presence of native biotinylated proteins might be used to control for possible loading artefacts. Finally, with regard to localization studies by fluorescence microscopy, it is very important to be aware of probe selectivity because, unlike protein blots, fluorescence microscopy does not permit the distinction of the target from off-targets. Preliminary selectivity studies should be performed to assess feasibility and to set up optimal experimental conditions.
Limitations of the described technique mainly pertain to the necessity of avoiding experimental conditions that can affect the CC reaction, such as the use of detergents and amine-containing buffers. These aspects must be taken in to account when preparing a cell lysate or a tissue homogenate. Moreover, when a streptavidin enrichment phase is required, the amount of starting material constitutes another issue, because this procedure is only applicable when the protein content is not less than 250 &#181;g. This limit is set due to technical issues, such as working volumes, protein recovery, after CC-induced precipitation, and the amount of streptavidin resin to be used.
Previously, NAAA activity could be only evaluated by performing activity assays, which require the use of an activation buffer for the in vitro activation of the enzyme and for substrate solubilization14. This approach provides information about total NAAA expression, not about the presence of active NAAA. Another possibility is to measure tissue levels of PEA and OEA, but this method represents only an indirect way to evaluate NAAA activity34,35. In addition, FAE levels can be influenced by other factors such as biosynthesis. The chemical probe ARN14686 is the first ABP for NAAA. The protocol described here illustrates a simple procedure for capturing and visualizing the active form of NAAA, both in vitro and in vivo. All sample manipulations are subsequent to probe-target reactions, thus giving reliable information about the in vivo state of the enzyme. Moreover, the use of ARN14686 in fluorescence microscopy represents a unique tool to localize active NAAA. Available antibodies, which recognize the NAAA catalytic subunit, do not discriminate between the NAAA full-length proenzyme and the active enzyme.
Starting from the protocol described here, NAAA expression and activation can be analyzed in different cell lines and animal models of inflammation. Co-localization studies can be performed to better characterize the role of NAAA in physiological and pathological conditions.

Commonly used methods to investigate the expression patterns, interactions, and functions of proteins, including liquid chromatography-mass spectrometry platforms for shotgun analysis1,2, yeast two-hybrid methods3,4, and in vitro assays, are limited in that they are unable to assess the activity of proteins in their native state. Activity-based protein profiling (ABPP) can be used to fill this gap. In this approach, small-molecule probes capable of covalently binding to the active site of an enzyme of interest are conjugated to a reporter group that allows for target detection. Using click chemistry (CC), the reporter can be integrated into the probe or can be introduced after target engagement has occurred5,6. The latter procedure requires the use of probes containing appropriate chemical groups, such as a terminal alkyne or azide, which can be modified with a number of reporter reagents via bio-orthogonal reactions such as the Cu(I)-catalyzed Huisgen [3+2] cycloaddition7-9 or Staudinger ligation10,11.
Recently, we disclosed the compound ARN14686 as the first ABP for the in vitro and in vivo detection of the cysteine hydrolase, NAAA12. NAAA catalyzes the hydrolytic deactivation of saturated and monounsaturated FAEs, including oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), which are endogenous agonists of the anti-inflammatory nuclear receptor PPAR-alpha13-15. NAAA is predominantly expressed in macrophages and other monocyte-derived cells, as well as in B-lymphocytes14,16, suggesting a role in the regulation of the innate immune response. The enzyme is synthesized in the rough endoplasmic reticulum in an inactive form and is activated in acidic compartments of the cell by an autoproteolytic mechanism17. The autoproteolytic cleavage generates a new N-terminal cysteine (C131 in mice and rats, C126 in humans), that is the nucleophile responsible for FAE hydrolysis18,19. Pharmacological inhibition of NAAA activity alters the FAE synthesis/degradation balance in favor of increased cellular levels of FAEs16,20,21. Several &#946;-lactone and &#946;-lactam derivatives have been shown to inhibit NAAA activity with high potency and selectivity16,22-26. These inhibitors act through S-acylation of the catalytic cysteine16,27,28.
The compound ARN14686 was designed based on the chemical structure of the systemically active, serine-derived &#946;-lactam NAAA inhibitor, ARN726 (4-cyclohexylbutyl-N-[(S)-2-oxoazetidin-3-yl]carbamate)16. The 4-butyl-cyclohexyl group of ARN726 was replaced with a C9 saturated aliphatic chain bearing a terminal alkyne tag for subsequent CC conjugation with an azide-bearing reporter tag. We chose to design a two-step ABP to minimally alter the structure of the original scaffold, thus maintaining the affinity of the probe for NAAA. Moreover, avoiding the introduction of bulky tags, such a probe could be more suitable for in vivo treatment than a direct ABP. ARN14686 inhibits NAAA with high potency (hNAAA IC50 = 6 nM, rNAAA IC50 = 13 nM) by forming a covalent adduct with the catalytic cysteine of the enzyme12. Experiments in live rats showed that the probe is selective in capturing NAAA expressed in lungs. Acid ceramidase, another cysteine amidase that shares 33-34% identity with NAAA, was also identified as a low-affinity target when using high probe concentrations (10 &#181;M in vitro, 10 mg/ml intravenous, i.v.)12. We have also used ARN14686 to study the presence of active NAAA in inflamed rat tissues following administration of complete Freund&#39;s adjuvant (CFA)29.
Here, we outline a protocol for the preparation of ARN14686 (Figure 1) and its application to the investigation of NAAA activation ex vivo. As an example, we describe an experimental procedure to visualize NAAA in rat paws after CFA administration. In this experiment, proteins are extracted from paw tissue after i.v. injection of the probe, and the ABP-labeled proteome is subjected to CC with biotin-azide. Biotinylated samples are enriched using streptavidin beads, and protein blots are performed. In another application, we describe the localization of active NAAA by fluorescence microscopy in mouse lungs from probe-treated mice. In this case, the tissue is sectioned and sections are subjected to CC for rhodamine addition. A workflow scheme is illustrated in Figure 2.

<table border="0" cellpadding="0" cellspacing="0" width="1209">
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		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">1,1&#8217;-sulfonyldiimidazole&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">367818</td>
			<td style="width:471px;">Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">2-dipyridylcarbonate</td>
			<td style="width:205px;">Fluorochem</td>
			<td style="width:111px;">11331</td>
			<td style="width:471px;">Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">2-Methylbutan</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">M32631</td>
			<td>Flamable, toxic,hazardous to the aquatic environment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">4-(Dimethylamino)pyridine</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">107700</td>
			<td style="width:471px;">Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Acetic acid</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">695092</td>
			<td style="width:471px;">Flammable, Corrosive</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Acetonitrile&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34998</td>
			<td style="width:471px;">Flammable, Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Activated charcoal</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">161551</td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Ammonium chloride</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">A9434</td>
			<td style="width:471px;">Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Azide-PEG3-Biotin</td>
			<td style="width:205px;">Jena Biosciences</td>
			<td style="width:111px;">CLK-AZ104P4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Azide-PEG3-Fluor 545</td>
			<td style="width:205px;">Jena Biosciences</td>
			<td style="width:111px;">CLK-AZ109</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">BCA protein assay kit</td>
			<td style="width:205px;">Thermo Fisher Scientific</td>
			<td style="width:111px;">23227</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Bio-spin columns</td>
			<td style="width:205px;">Biorad</td>
			<td style="width:111px;">732-6204</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Biotin</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">B4501</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Blocking buffer</td>
			<td style="width:205px;">Li-Cor Biosciences</td>
			<td style="width:111px;">927-40000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">b-mercaptoethanol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">M6250</td>
			<td>Higly toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Bovin serum albumine (BSA)</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">A7030</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Bromophenol blue</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">B0126</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Bruker Avance III 400</td>
			<td style="width:205px;">Bruker</td>
			<td style="width:111px;"></td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Celite</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">419931</td>
			<td style="width:471px;">Health hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Ceric ammonium nitrate&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">22249</td>
			<td style="width:471px;">Oxidizing, Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Chloral hydrate</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">C8383</td>
			<td>Higly toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">CuSO4.5H2O&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">209198</td>
			<td>Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Cyclohexadiene</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">125415</td>
			<td style="width:471px;">Flammable, Health hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Cyclohexane</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34855</td>
			<td style="width:471px;">Flammable, Harmful, Health hazard, Environmental hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Dichloromethane</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34856</td>
			<td style="width:471px;">Harmful, Health hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Diethyl ether</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">296082</td>
			<td style="width:471px;">Flammable, Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Dimethyl sulfoxide (DMSO)</td>
			<td style="width:205px;">Acros Organics</td>
			<td style="width:111px;">348441000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Dimethyl sulfoxide d6 (DMSO-d6)</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">175943</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Ethanol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">2860</td>
			<td style="width:471px;">Flammable, Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Ethyl acetate</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34858</td>
			<td style="width:471px;">Flammable, Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Glycerol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">G5516</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Irdye 680-LT Streptavidin</td>
			<td style="width:205px;">Li-Cor Biosciences</td>
			<td style="width:111px;">925-68031</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">IRDye680-LT Streptavidin&#160;</td>
			<td style="width:205px;">Licor</td>
			<td style="width:111px;">925-68031</td>
			<td>Briefly centrifuge before use to precipitate protein complexes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Methanol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34966</td>
			<td>Highly toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Methanol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">34860</td>
			<td style="width:471px;">Flammable, Toxic, Health hazard</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:423px;">N-(3-Dimethylaminopropyl)-N&#8242;-ethylcarbodiimide hydrochloride</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">E7750</td>
			<td style="width:471px;">Harmful, Corrosive</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">N,N-diisopropylethylamine</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">D125806</td>
			<td style="width:471px;">Flammable, Corrosive, Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">N,N-dimethylformamide</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">227056</td>
			<td style="width:471px;">Flammable, Harmful, Health hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">N-Cbz-L-Serine</td>
			<td style="width:205px;">Fluorochem&#160;</td>
			<td style="width:111px;">M03053</td>
			<td style="width:471px;">Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Nikon A1 confocal microscopy</td>
			<td style="width:205px;">Nikon</td>
			<td style="width:111px;"></td>
			<td>Read&#160; the user manual</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">NuPAGE 4-12% Bis-Tris gel</td>
			<td style="width:205px;">Thermo Fisher Scientific</td>
			<td style="width:111px;">NP0335BOX</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Palladium on carbon</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">330108</td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">p-anisidine</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">A88255</td>
			<td style="width:471px;">Toxic, Health hazard, Environmental hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Paraformaldehyde</td>
			<td style="width:205px;">sigma Aldrich</td>
			<td style="width:111px;">441244</td>
			<td>Toxic, respiratory harmful, corrosive, falmable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Poly(ethylene glycol)&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">P3265</td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">ProLong Gold antifade mountant with DAPI&#160;</td>
			<td style="width:205px;">Thermo Fisher Scientific</td>
			<td style="width:111px;">P36931</td>
			<td>Avoid bubbles formation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Protease inhibitor cocktail</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">P8340</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Sodium bicarbonate</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">S6014</td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Sodium dodecyl sulfate (SDS)&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">L3771</td>
			<td>Toxic, corrosive, falmmable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Sodium hydride&#160;</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">452912</td>
			<td style="width:471px;">Flammable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Sodium sulfate</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">239313</td>
			<td style="width:471px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Starion FLA-9000 immage scanner</td>
			<td style="width:205px;">FUJIFILM</td>
			<td style="width:111px;"></td>
			<td>Read&#160; the user manual</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Streptavidin agarose</td>
			<td style="width:205px;">Thermo Fisher Scientific</td>
			<td>20349</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Sucrose</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">S7903</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Tert-butanol</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">360538</td>
			<td>Toxic, flammable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Tetrahydrofuran</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">186562</td>
			<td style="width:471px;">Flammable, Harmful, Health hazard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Thiourea</td>
			<td style="width:205px;">Acros Organics</td>
			<td style="width:111px;">424542500</td>
			<td>Toxic, warm at 50 &#176;C to dissolve</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Tris</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">RDD008</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tris(2-carboxyethyl)phosphine (TCEP)</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">C4706</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA)</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">678937</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Triton-x100</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">X100</td>
			<td>Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Tween-20</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">P9416</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Tween-80</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">P1754</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Ultra turrax IKA T18 basic tissue homogenizer</td>
			<td style="width:205px;">IKA</td>
			<td style="width:111px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Undec-10-yn-1-ol</td>
			<td style="width:205px;">Fluorochem</td>
			<td style="width:111px;">13739</td>
			<td style="width:471px;">Harmful</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:423px;">Urea</td>
			<td style="width:205px;">Sigma Aldrich</td>
			<td style="width:111px;">U5378</td>
			<td>Toxic, warm at 50 &#176;C to dissolve</td>
		</tr>
	</tbody>
</table>

preparation and in vivo use of an activity-based probe for n-acylethanolamine acid amidase

Activity-based protein profiling (ABPP) is a method for the identification of an enzyme of interest in a complex proteome through the use of a chemical probe that targets the enzyme&#39;s active sites. A reporter tag introduced into the probe allows for the detection of the labeled enzyme by in-gel fluorescence scanning, protein blot, fluorescence microscopy, or liquid chromatography-mass spectrometry. Here, we describe the preparation and use of the compound ARN14686, a click chemistry activity-based probe (CC-ABP) that selectively recognizes the enzyme N-acylethanolamine acid amidase (NAAA). NAAA is a cysteine hydrolase that promotes inflammation by deactivating endogenous peroxisome proliferator-activated receptor (PPAR)-alpha agonists such as palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). NAAA is synthesized as an inactive full-length proenzyme, which is activated by autoproteolysis in the acidic pH of the lysosome. Localization studies have shown that NAAA is predominantly expressed in macrophages and other monocyte-derived cells, as well as in B-lymphocytes. We provide examples of how ARN14686 can be used to detect and quantify active NAAA ex vivo in rodent tissues by protein blot and fluorescence microscopy.

ARN14686 was designed based on the scaffold of the NAAA inhibitor ARN726. The 4-butyl-cyclohexyl group of ARN726 was substituted with a C9 saturated aliphatic chain bearing a terminal alkyne tag (Figure 1). The alkyne tag was introduced in order to allow the use of a two-step labeling procedure to add a fluorophore or a biotin molecule via CC. This feature renders ARN14686 a very versatile tool to probe NAAA in vitro and in vivo.
Here, we show two applications of ARN14686, which are representative of the potential of this molecule. Figure 2 is a scheme of the experimental procedure reported here. After i.v. administration of the probe, two different detection methods can be used: i) analysis of active NAAA expression by protein blot and ii) analysis of active NAAA expression and localization within cells by fluorescence microscopy.
The first representative result was recently published by our group29. We analyzed NAAA expression in a rat model of CFA-induced paw inflammation. The probe (3 mg/kg) or vehicle was injected i.v. in na&#239;ve and CFA-treated rats. The rats were sacrificed 4 hr later. CC was performed on enriched lysosomal extracts to introduce a biotin-tag onto the probe-labeled proteins. Biotinylated proteins were next enriched using streptavidin beads. The eluted proteins were analyzed by protein blot, showing that levels of active NAAA were markedly increased in the paws of rats treated with CFA relative to those of control rats (Figure 3). The advantage of protein blot analysis is that it enables a detailed examination of the probe-reactive proteome, which is separated by gel electrophoresis. This approach also allows for the unveiling of potential probe off-targets. A no-probe control must be always included in order to exclude endogenous biotinylated proteins, which constitute the experimental background. The arrowhead in Figure 3 indicates such background proteins, which in turn can be used as a loading reference control.
In a second unpublished experiment (Figure 4), we used ARN14686 to probe NAAA for ex vivo detection by fluorescence microscopy. We administered ARN14686 to mice at 3 mg/kg (i.v.) and sacrificed them 2 hr after treatment by transcardial perfusion. Lungs were collected, postfixed, and frozen in cold 2-metylbutane. The CC reaction for fluorophore addition was performed directly on tissue slices of 40 &#181;m thickness, collected with a cryostat. Analysis by fluorescence microscopy showed the presence of catalytically active NAAA in diffused vesicular structures belonging to alveolar macrophages. Compared to the use of a protein-specific antibody, only the active enzyme is observed.
<img alt="Figure 1" src="/files/ftp_upload/54652/54652fig1.jpg" /> 
&#160; &#160; 
Figure 1: ARN14686 synthesis reaction scheme. Undec-10-yn-2-ol was activated by dipyridylcarbonate (DPC) in the presence of catalytic 4-dimethylaminopyridine (DMAP) to produce a mixed carbonate. This carbonate was then reacted with the amino lactam to obtain the target molecule ARN14686. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54652/54652fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/54652/54652fig2.jpg" /> 
Figure 2: Workflow scheme of the general strategy shown in the present work. The probe is injected into animals (rats or mice) and target expression is analyzed following two different experimental procedures: i) The labeled proteome is extracted and biotin is added by CC. After an enrichment phase of biotinylated proteins on streptavidin beads, probe targets are analyzed by protein blot. ii) Tissue slices are prepared and a fluorophore is added by CC. Probe target localization is analyzed by florescence microscopy. This figure has been adapted from Bonezzi et al.29 <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54652/54652fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/54652/54652fig3.jpg" /> 
Figure 3: Analysis of NAAA activation in paws of CFA-treated rats. Protein blot analysis of streptavidin-enriched proteins from na&#239;ve rats (lanes 1 and 2) or CFA-injected rats 7 days after injection (lanes 3 and 4). Rats received i.v. injections of vehicle or ARN14686 (3 mg/kg). The blotting membrane was probed with a fluorescent streptavidin. The arrow indicates the NAAA band; the arrowhead indicates a biotin-containing band of around 90 kDa, showing that a similar amount of protein was loaded in each lane. This figure has been modified from Bonezzi et al.29 <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54652/54652fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" src="/files/ftp_upload/54652/54652fig4.jpg" /> 
Figure 4: Ex vivo detection of probe-labeled NAAA in mouse lungs by fluorescence microscopy. Representative pictures of lung sections of vehicle- (A) or ARN14686-injected (B) mice after CC with azide-PEG3-Fluor 545 are reported. A positive signal (red cells) was detected in ARN14686-injected mice, while no signal was detected in vehicle-administered mice. A detail of an azide-PEG3-Fluor 545 positive alveolar macrophage is shown in C at higher magnification. Nuclei were marked with DAPI (blue). Scale bar = 50 &#181;m in A and 10 &#181;m in C. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54652/54652fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase at JoVE.com

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

Here, we describe the preparation and use of an activity-based probe (ARN14686, undec-10-ynyl-N-[(3S)-2-oxoazetidin-3-yl]carbamate) that allows for the detection and quantification of the active form of the proinflammatory enzyme N-acylethanolamine acid amidase (NAAA), both in vitro and ex vivo.

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

Activity-based protein profiling (ABPP) is a method for the identification of an enzyme of interest in a complex proteome through the use of a chemical ...

preparation-vivo-use-an-activity-based-probe-for-n-acylethanolamine

Nanyang Technological University

Research

JoVE Journal

Biochemistry

9.6K Views.  Istituto Italiano di Tecnologia. Here, we describe the preparation and use of an activity-based probe (ARN14686, undec-10-ynyl-N-[(3S)-2-oxoazetidin-3-yl]carbamate) that allows for the detection and quantification of the active form of the proinflammatory enzyme N-acylethanolamine acid amidase (NAAA), both in vitro and ex vivo.

Video: Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

An Efficient Method for the Isolation of Highly Purified RNA from Seeds for Use in Quantitative Transcriptome Analysis

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as industrial materials. Gene expression profiles are powerful tools for investigating metabolic regulation in plant cells. Therefore, detailed, accurate gene expression profiles during seed development are required for crop breeding. Acquiring highly purified RNA is essential for producing these profiles. Efficient methods are needed to isolate highly purified RNA from seeds. Here, we describe a method for isolating RNA from seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method enables highly purified RNA to be obtained from seeds without the use of phenol, chloroform, or additional processes for RNA purification. This method is applicable to Arabidopsis, rapeseed, and soybean seeds. Our method will be useful for monitoring the expression patterns of low level transcripts in developing and mature seeds.

We have succeeded in establishing a method for RNA isolation from plant seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method is suitable for monitoring the expression of genes with low level transcripts in seeds.

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as ...

Preparation of Giant Vesicles Encapsulating Microspheres by Centrifugation of a Water-in-oil Emulsion

The constructive biology and the synthetic biology approach to creating artificial life involve the bottom-up assembly of biological or nonbiological materials. Such approaches have received considerable attention in research on the boundary between living and nonliving matter and have been used to construct artificial cells over the past two decades. In particular, Giant Vesicles (GVs) have often been used as artificial cell membranes. In this paper, we describe the preparation of GVs encapsulating highly packed microspheres as a model of cells containing highly condensed biomolecules. The GVs were prepared by means of a simple water-in-oil emulsion centrifugation method. Specifically, a homogenizer was used to emulsify an aqueous solution containing the materials to be encapsulated and an oil containing dissolved phospholipids, and the resulting emulsion was layered carefully on the surface of another aqueous solution. The layered system was then centrifuged to generate the GVs. This powerful method was used to encapsulate materials ranging from small molecules to microspheres.

Giant vesicles containing highly packed micrometer-sized components are useful cell models. The water-in-oil emulsion centrifugation method is a simple, powerful tool for the preparation of giant vesicles with encapsulated materials.

The constructive biology and the synthetic biology approach to creating artificial life involve the bottom-up assembly of biological or nonbiological ...

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most cases, the action of noncoding RNAs is mediated by proteins whose functions are in turn regulated by these interactions with noncoding RNAs. Consistent with this, a growing number of proteins involved in nuclear functions have been reported to bind RNA and in a few cases the RNA-binding regions of these proteins have been mapped, often through laborious, candidate-based methods.
Here, we report a detailed protocol to perform a high-throughput, proteome-wide unbiased identification of RNA-binding proteins and their RNA-binding regions. The methodology relies on the incorporation of a photoreactive uridine analog in the cellular RNA, followed by UV-mediated protein-RNA crosslinking, and mass spectrometry analyses to reveal RNA-crosslinked peptides within the proteome. Although we describe the procedure for mouse embryonic stem cells, the protocol should be easily adapted to a variety of cultured cells.

We describe a protocol to identify RNA-binding proteins and map their RNA-binding regions in live cells using UV-mediated photocrosslinking and mass spectrometry.

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most ...

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.

The goal of the protocol is to prepare keratin hydrolysate from chicken feathers by alkaline-enzymatic hydrolysis and to test whether adding keratin hydrolysate into a cosmetics ointment base improves skin barrier function (heightening hydration and diminishing transepidermal water loss). Tests are conducted on men and woman volunteers.

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for ...

Use of Alu Element Containing Minigenes to Analyze Circular RNAs

In addition to linear mRNAs, many eukaryotic genes generate circular RNAs. Most circular RNAs are generated by joining a 5&#39; splice site with an upstream 3&#39; splice site within a pre-mRNA, a process called back-splicing. This circularization is likely aided by secondary structures in the pre-mRNA that bring the splice sites into close proximity. In human genes, Alu elements are thought to promote these secondary RNA structures, as Alu elements are abundant and exhibit base complementarities with each other when present in opposite directions in the pre-mRNA. Here, we describe the generation and analysis of large, Alu element containing reporter genes that form circular RNAs. Through optimization of cloning protocols, reporter genes with up to 20 kb insert length can be generated. Their analysis in co-transfection experiments allows the identification of regulatory factors. Thus, this method can identify RNA sequences and cellular components involved in circular RNA formation.

Use of Alu Element Containing Minigenes to Analyze Circular RNAs

We clone and analyze reporter genes generating circular RNAs. These reporter genes are larger than constructs to analyze linear splicing and contain Alu elements. To investigate the circular RNAs, the constructs are transfected into cells and resulting RNA is analyzed using RT-PCR after removal of linear RNA.

In addition to linear mRNAs, many eukaryotic genes generate circular RNAs. Most circular RNAs are generated by joining a 5&#39; splice site with an ...

A Plasma Sample Preparation for Mass Spectrometry using an Automated Workstation

Sample preparation for mass spectrometry analysis in proteomics requires enzymatic cleavage of proteins into a peptide mixture. This process involves numerous incubation and liquid transfer steps in order to achieve denaturation, reduction, alkylation, and cleavage. Adapting this workflow onto an automated workstation can increase efficiency and reduce coefficients of variance, thereby providing more reliable data for statistical comparisons between sample types. We previously described an automated proteomic sample preparation workflow1. Here, we report the development of a more efficient and better controlled workflow with the following advantages: 1) The number of liquid transfer steps is reduced from nine to six by combining reagents; 2) Pipetting time is reduced by selective tip pipetting using a 96-position pipetting head with multiple channels; 3) Potential throughput is increased by the availability of up to 45 deck positions; 4) Complete enclosure of the system provides improved temperature and environmental control and reduces the potential for contamination of samples or reagents; and 5) The addition of stable isotope labeled peptides, as well as &#946;-galactosidase protein, to each sample makes monitoring and quality control possible throughout the entire process. These hardware and process improvements provide good reproducibility and improve intra-assay and inter-assay precision (CV of less than 20%) for LC-MS based protein and peptide quantification. The entire workflow for digesting 96 samples in a 96-well plate can be completed in approximately 5 hours.

Here, we present an automated plasma protein digestion method for mass spectrometry-based quantitative proteomic analysis. In this protocol, the liquid transferring and incubation steps for protein denaturation, reduction, alkylation, and trypsin digestion reactions are streamlined and automated. It takes approximately five hours to prepare a 96-well plate with desired precision.

Sample preparation for mass spectrometry analysis in proteomics requires enzymatic cleavage of proteins into a peptide mixture. This process involves ...

Sample Preparation for Probe Electrospray Ionization Mass Spectrometry

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ratios (m/z), which are useful to deduce molecular weights and structures. While it is essentially a destructive analytical method, recent advancements in the ambient ionization technique have enabled us to acquire data while leaving tissue in a relatively intact state in terms of integrity. Probe electrospray ionization (PESI) is a so-called direct method because it does not require complex and time-consuming pretreatment of samples. A fine needle serves as a sample picker, as well as an ionization emitter. Based on the very sharp and fine property of the probe tip, destruction of the samples is minimal, allowing us to acquire the real-time molecular information from living things in situ. Herein, we introduce three applications of PESI-MS technique that will be useful for biomedical research and development. One involves the application to solid tissue, which is the basic application of this technique for the medical diagnosis. As this technique requires only 10 mg of the sample, it may be very useful in the routine clinical settings. The second application is for in vitro medical diagnostics where human blood serum is measured. The ability to measure fluid samples is also valuable in various biological experiments where a sufficient volume of sample for conventional analytical techniques cannot be provided. The third application leans toward the direct application of probe needles in living animals, where we can obtain real-time dynamics of metabolites or drugs in specific organs. In each application, we can infer the molecules that have been detected by MS or use artificial intelligence to obtain a medical diagnosis.

This article introduces sample preparation methods for a unique real-time analytical method based on the ambient mass spectrometry. This method lets us perform real-time analysis of the biological molecules in vivo without any special pretreatments.

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ...

Preparation of High-Quality Fermented Fish Product

This protocol provides a method for preparation of industrialized fermented fish product with sturgeon (Aquilaria sinensis) meat product. The procedures were: (1) pretreatment of farmed sturgeon including decapitation, evisceration, skinning-off, cleaning and cutting; (2) marinating fish cubes in 6-12% (w/v) salt solution (1:1, fish cube mass to solution volume); (3) drying fish cubes to a water content of 50-60% by hot air (40-60 &#176;C) or by vacuum; (4) fermentation involving inoculating fish cubes with 0.4-1.6% (w/w) S. cerevisiae in flavor solution to fish cubes and fermenting at 25-35 &#176;C for 6-10 h; (5) sealing fish cubes in vacuum packages with marinating and fermenting solutions; (6) sterilizing at 115-121 &#176;C for 10-20 min. The sturgeon meat product prepared by this method has delicious taste which is mellow and thick, has various types and large amounts of volatile flavor compounds such as alcohols and esters which could mask musty and unpleasant odor from fish, has moderate salt content but good texture properties such as high springiness, gumminess and chewiness, and has bright russet color and attractive appearance. This new technique could also be applied in the processing of other fish to provide convenient fish snack foods which could be stored at room temperature. It is appropriate for both marine and freshwater fish.

The goal of the protocol is to provide an industrialized fish fermentation technique based on inoculation of Saccharomyces cerevisiae.

This protocol provides a method for preparation of industrialized fermented fish product with sturgeon (Aquilaria sinensis) meat product. The procedures ...

Use of Microscale Thermophoresis to Measure Protein-Lipid Interactions

The ability to determine the binding affinity of lipids to proteins is an essential part of understanding protein-lipid interactions in membrane trafficking, signal transduction and cytoskeletal remodeling. Classic tools for measuring such interactions include surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). While powerful tools, these approaches have setbacks. ITC requires large amounts of purified protein as well as lipids, which can be costly and difficult to produce. Furthermore, ITC as well as SPR are very time consuming, which could add significantly to the cost of performing these experiments. One way to bypass these restrictions is to use the relatively new technique of microscale thermophoresis (MST). MST is fast and cost effective using small amounts of sample to obtain a saturation curve for a given binding event. There currently are two types of MST systems available. One type of MST requires labeling with a fluorophore in the blue or red spectrum. The second system relies on the intrinsic fluorescence of aromatic amino acids in the UV range. Both systems detect the movement of molecules in response to localized induction of heat from an infrared laser. Each approach has its advantages and disadvantages. Label-free MST can use untagged native proteins; however, many analytes, including pharmaceuticals, fluoresce in the UV range, which can interfere with determination of accurate KD values. In comparison, labeled MST allows for a greater diversity of measurable pairwise interactions utilizing fluorescently labeled probes attached to ligands with measurable absorbances in the visible range as opposed to UV, limiting the potential for interfering signals from analytes.

Microscale thermophoresis obtains binding constants quickly at low material cost. Either labeled or label free microscale thermophoresis is commercially available; however, label free thermophoresis is not capable of the diversity of interaction measurements that can be performed using fluorescent labels. We provide a protocol for labeled thermophoresis measurements.

The ability to determine the binding affinity of lipids to proteins is an essential part of understanding protein-lipid interactions in membrane ...

Plant Sample Preparation for Nucleoside/Nucleotide Content Measurement with An HPLC-MS/MS

Nucleosides/nucleotides are building blocks of nucleic acids, parts of cosubstrates and coenzymes, cell signaling molecules, and energy carriers, which are involved in many cell activities. Here, we describe a rapid and reliable method for the absolute qualification of nucleoside/nucleotide contents in plants. Briefly, 100 mg of homogenized plant material was extracted with 1 mL of extraction buffer (methanol, acetonitrile, and water at a ratio of 2:2:1). Later, the sample was concentrated five times in a freeze dryer and then injected into an HPLC-MS/MS. Nucleotides were separated on a porous graphitic carbon (PGC) column and nucleosides were separated on a C18 column. The mass transitions of each nucleoside and nucleotide were monitored by mass spectrometry. The contents of the nucleosides and nucleotides were quantified against their external standards (ESTDs). Using this method, therefore, researchers can easily quantify nucleosides/nucleotides in different plants.

A precise and reproducible method for in vivo nucleosides/nucleotides quantification in plants is described here. This method employs an HPLC-MS/MS.

Nucleosides/nucleotides are building blocks of nucleic acids, parts of cosubstrates and coenzymes, cell signaling molecules, and energy carriers, which ...

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase

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Chapters in this video

An Efficient Method for the Isolation of Highly Purified RNA from Seeds for Use in Quantitative Transcriptome Analysis

Preparation of Giant Vesicles Encapsulating Microspheres by Centrifugation of a Water-in-oil Emulsion

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics

Use of Alu Element Containing Minigenes to Analyze Circular RNAs

A Plasma Sample Preparation for Mass Spectrometry using an Automated Workstation

Sample Preparation for Probe Electrospray Ionization Mass Spectrometry

Preparation of High-Quality Fermented Fish Product

Use of Microscale Thermophoresis to Measure Protein-Lipid Interactions

Plant Sample Preparation for Nucleoside/Nucleotide Content Measurement with An HPLC-MS/MS