The authors are very thankful for the technical assistance by Ayse &#214;zt&#252;rk and Eva Albertini. Mice used for the generation of liver tissue were maintained under the supervision of Univ.-Doz. Dr. Pidder Jansen-D&#252;rr (Institute for Biomedical Aging Research at Innsbruck University, Rennweg 10, 6020 Innsbruck, Austria).

<ol>
	<li>Pircher, H., 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=Identification+of+FAH+domain-containing+protein+1+(FAHD1)+as+oxaloacetate+decarboxylase.">Identification of FAH domain-containing protein 1 (FAHD1) as oxaloacetate decarboxylase.</a> Journal of Biological Chemistry. 290 (11), 6755-6762 (2015).</li><li>Pircher, H., 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=Identification+of+human+Fumarylacetoacetate+Hydrolase+Domain-containing+Protein+1+(FAHD1)+as+a+novel+mitochondrial+acylpyruvase.">Identification of human Fumarylacetoacetate Hydrolase Domain-containing Protein 1 (FAHD1) as a novel mitochondrial acylpyruvase.</a> Journal of Biological Chemistry. 286 (42), 36500-36508 (2011).</li><li>Kang, T. -. W., 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=Senescence+surveillance+of+pre-malignant+hepatocytes+limits+liver+cancer+development.">Senescence surveillance of pre-malignant hepatocytes limits liver cancer development.</a> Nature. 479 (7374), 547-551 (2011).</li><li>Hong, H., Seo, H., Park, W., Kim, K. K. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequence,+structure+and+function-based+classification+of+the+broadly+conserved+FAH+superfamily+reveals+two+distinct+fumarylpyruvate+hydrolase+subfamilies.">Sequence, structure and function-based classification of the broadly conserved FAH superfamily reveals two distinct fumarylpyruvate hydrolase subfamilies.</a> Environmental Microbiology. 22 (1), 270-285 (2020).</li><li>Timm, D. E., Mueller, H. A., Bhanumoorthy, P., Harp, J. M., Bunick, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystal+structure+and+mechanism+of+a+carbon-carbon+bond+hydrolase.">Crystal structure and mechanism of a carbon-carbon bond hydrolase.</a> Structure. 7 (9), 1023-1033 (1999).</li><li>Bateman, R. L., 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=Mechanistic+inferences+from+the+crystal+structure+of+Fumarylacetoacetate+Hydrolase+with+a+bound+phosphorus-based+inhibitor.">Mechanistic inferences from the crystal structure of Fumarylacetoacetate Hydrolase with a bound phosphorus-based inhibitor.</a> Journal of Biological Chemistry. 276 (18), 15284-15291 (2001).</li><li>Weiss, A. K. H., 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=Structural+basis+for+the+bi-functionality+of+human+oxaloacetate+decarboxylase+FAHD1.">Structural basis for the bi-functionality of human oxaloacetate decarboxylase FAHD1.</a> Biochemical Journal. 475 (22), 3561-3576 (2018).</li><li>Etemad, 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=Oxaloacetate+decarboxylase+FAHD1+-+a+new+regulator+of+mitochondrial+function+and+senescence.">Oxaloacetate decarboxylase FAHD1 - a new regulator of mitochondrial function and senescence.</a> Mechanisms of Ageing and Development. 177, 22-29 (2019).</li><li>Weiss, A. K. H., 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=Regulation+of+cellular+senescence+by+eukaryotic+members+of+the+FAH+superfamily+-+A+role+in+calcium+homeostasis.">Regulation of cellular senescence by eukaryotic members of the FAH superfamily - A role in calcium homeostasis.</a> Mechanisms of Ageing and Development. 190, 111284 (2020).</li><li>Petit, M., Koziel, R., Etemad, S., Pircher, H., Jansen-D&#252;rr, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Depletion+of+oxaloacetate+decarboxylase+FAHD1+inhibits+mitochondrial+electron+transport+and+induces+cellular+senescence+in+human+endothelial+cells.">Depletion of oxaloacetate decarboxylase FAHD1 inhibits mitochondrial electron transport and induces cellular senescence in human endothelial cells.</a> Experimental Gerontology. 92, 7-12 (2017).</li><li>Wiley, C. D., 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=Mitochondrial+dysfunction+induces+senescence+with+a+distinct+secretory+phenotype.">Mitochondrial dysfunction induces senescence with a distinct secretory phenotype.</a> Cell Metabolism. 23 (2), 303-314 (2016).</li><li>Weiss, A. K. H., 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=Expression,+purification,+crystallization,+and+enzyme+assays+of+Fumarylacetoacetate+Hydrolase+Domain-containing+proteins.">Expression, purification, crystallization, and enzyme assays of Fumarylacetoacetate Hydrolase Domain-containing proteins.</a> Journal of Visualized Experiments: JoVE. (148), e59729 (2019).</li><li>Weiss, A. K. H., 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=Inhibitors+of+Fumarylacetoacetate+Hydrolase+Domain+Containing+Protein+1+(FAHD1).">Inhibitors of Fumarylacetoacetate Hydrolase Domain Containing Protein 1 (FAHD1).</a> Molcules. 26 (16), 5009 (2021).</li><li>Mizutani, H., Kunishima, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification,+crystallization+and+preliminary+X-ray+analysis+of+the+fumarylacetoacetase+family+member+TTHA0809+from+Thermus+thermophilus+HB8.">Purification, crystallization and preliminary X-ray analysis of the fumarylacetoacetase family member TTHA0809 from Thermus thermophilus HB8.</a> Acta Crystallographica Section F Structural Biology and Crystallization Communications. 63 (9), 792-794 (2007).</li><li>Lee, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+outline+of+methods+for+protein+isolation+and+purification.">A simple outline of methods for protein isolation and purification.</a> Endocrinology and Metabolism. 32 (1), 18-22 (2017).</li><li>Amer, H. E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+proteins:+Between+meaning+and+different+methods).">Purification of proteins: Between meaning and different methods).</a> Proteomics Technologies and Applications. , (2019).</li><li>Niu, L., Yuan, H., Gong, F., Wu, X., Wang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+extraction+methods+shape+much+of+the+extracted+proteomes.">Protein extraction methods shape much of the extracted proteomes.</a> Frontiers in Plant Science. 9, 802 (2018).</li><li>Gordon, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+vanadate+as+protein-phosphotyrosine+phosphatase+inhibitor.">Use of vanadate as protein-phosphotyrosine phosphatase inhibitor.</a> Methods in Enzymology. 201, 477-482 (1991).</li><li>Gallagher, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SDS-polyacrylamide+gel+electrophoresis+(SDS-PAGE).">SDS-polyacrylamide gel electrophoresis (SDS-PAGE).</a> Current Protocols in Essential Laboratory Techniques. , (2012).</li><li>. Effect of pH on Protein Size Exclusion Chromatography Available from: <a target="_blank" href="https://www.agilent.com/cs/library/applications/5990-8138EN.pdf">https://www.agilent.com/cs/library/applications/5990-8138EN.pdf</a> (2011)</li><li>S&#248;rensen, B. 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=Silver+staining+of+proteins+on+electroblotting+membranes+and+intensification+of+silver+staining+of+proteins+separated+by+polyacrylamide+gel+electrophoresis.">Silver staining of proteins on electroblotting membranes and intensification of silver staining of proteins separated by polyacrylamide gel electrophoresis.</a> Analytical Biochemistry. 304 (1), 33-41 (2002).</li><li>Fagerberg, L., 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=Analysis+of+the+human+tissue-specific+expression+by+genome-wide+integration+of+transcriptomics+and+antibody-based+proteomics.">Analysis of the human tissue-specific expression by genome-wide integration of transcriptomics and antibody-based proteomics.</a> Molecular &amp; Cellular Proteomics. 13 (2), 397-406 (2014).</li><li>. Cytiva Life Fundamentals of size exclusion chromatography Available from: <a target="_blank" href="https://www.cytivalifesciences.com/en/us/solutions/protein-research/knowledge-center/protein-purification-methods/size-exclusion-chromatography">https://www.cytivalifesciences.com/en/us/solutions/protein-research/knowledge-center/protein-purification-methods/size-exclusion-chromatography</a> (2022)</li><li>Rosano, G. L., Ceccarelli, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombinant+protein+expression+in+Escherichia+coli:+advances+and+challenges.">Recombinant protein expression in Escherichia coli: advances and challenges.</a> Frontiers in Microbiology. 5, 172 (2014).</li><li>Rosano, G. L., Morales, E. S., Ceccarelli, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+tools+for+recombinant+protein+production+in+Escherichia+coli:+A+5-year+update.">New tools for recombinant protein production in Escherichia coli: A 5-year update.</a> Protein Science: A Publication of the Protein Society. 28 (8), 1412-1422 (2019).</li></ol>

The authors have no competing financial interests.

Critical steps in the protocol 
Following common guidelines for the handling of proteins is essential, such as working on ice and at moderate pH and salt conditions. The use of protease inhibitors is beneficial to the method, while the use of proteasome inhibitors is highly recommended. Freezing and thawing the sample may always result in protein precipitation (at least partially), so any thawed aliquot of initial protein lysate (step 2) should be processed continuously without a break. Centrifugati...

The eukaryotic FAH domain-containing protein 1 (FAHD1) acts as bi-functional oxaloacetate (OAA) decarboxylase (ODx)1 and acylpyruvate hydrolase (ApH)2. It is localized in mitochondria2 and belongs to the broad FAH superfamily of enzymes1,2,3,4,5,6. While its ApH activity is only of minor relevance, the ODx activity of FAHD1 is involved in the regulation of the TCA cycle flux1,7,8,9. OAA is not only required for the central citrate synthase reaction in the tricarboxylic acid cycle but also acts as a competitive inhibitor of succinate dehydrogenase as part of the electron transport system and as a cataplerotic metabolite. Downregulation of FAHD1 gene expression in human umbilical vein endothelial cells (HUVEC) resulted in a significant reduction in the rate of cell proliferation10, and significant inhibition of mitochondrial membrane potential, associated with a concomitant switch to glycolysis. The working model refers to mitochondrial dysfunction associated senescence (MiDAS)11-like phenotype8, where mitochondrial OAA levels are tightly regulated by FAHD1 activity1,8,9.
Recombinant protein is easier to obtain via expression and purification from bacteria12 rather than from tissue. However, a protein expressed in bacteria may be biased by possible lack of post-translational modifications, or may simply be problematic (i.e., due to plasmid loss, bacterial stress responses, distorted/unformed disulfide bonds, none or poor secretion, protein aggregation, proteolytic cleavage, etc.). For certain applications, protein needs to be obtained from cell lysate or tissue, in order to include such modifications and/or to exclude possible artifacts. Purified protein from tissue supports the development of high-quality antibodies, and/or potent and specific pharmacological inhibitors for selected enzymes, such as for FAHD113.
This manuscript presents a series of methods for the extraction and purification of FAHD1 from swine kidney and mouse liver. The described methods require fast protein liquid chromatography (FPLC) but otherwise use common laboratory equipment. Alternative methods may be found elsewhere14,15,16,17. After total protein extraction, the proposed protocol involves a testing phase, in which sub-protocols for ammonium sulfate precipitation and ionic exchange chromatography are discussed (Figure 1). After defining these sub-protocols, the protein of interest is extracted via a sequential strategy using ionic exchange and size-exclusion chromatography with FPLC. Based on these guidelines, the final protocol may be adapted individually for other proteins of interest.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63333/63333fig01.jpg" /> 
Figure 1: The overall strategy of this protocol. From top to bottom: Protein is extracted from tissues. Tissue homogenate is prepared, centrifuged, and filtrated. For each pair of supernatant and pellet-derived samples, tests for ammonium sulfate precipitation and ionic exchange chromatography (FPLC) need to be performed to probe for optimal conditions. After establishing these sub-protocols, the protein may be extracted via a sequential procedure of ammonium sulfate precipitation, ionic exchange chromatography, and repetitive size exclusion chromatography (FPLC) at varying pH and salt concentrations. All steps need to be controlled by western blot. <a href="https://www.jove.com/files/ftp_upload/63333/63333fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.22 &#181;m filter units</td>
			<td>MERCK</td>
			<td>SLGP033RS</td>
			<td>Millex-HP, 0.22 &#181;m, PES 33 mm, not steril</td>
		</tr>
		<tr>
			<td>0.45 &#181;m filter units</td>
			<td>MERCK</td>
			<td>SLHP033NS</td>
			<td>Millex-HP, 0.45 &#181;m, PES 33 mm, not steril</td>
		</tr>
		<tr>
			<td>15 mL Falcon tubes</td>
			<td>VWR</td>
			<td>734-0451</td>
			<td>centrifugal tubes</td>
		</tr>
		<tr>
			<td>50 mL Falcon tubes</td>
			<td>VWR</td>
			<td>734-0448</td>
			<td>centrifugal tubes</td>
		</tr>
		<tr>
			<td>96-Well UV Microplate</td>
			<td>Thermo-Fischer</td>
			<td>8404</td>
			<td>UV/VIS transparent flat-bottom 96 well plates</td>
		</tr>
		<tr>
			<td>Acrylamide/Bis Solution (40%, 29:1 ratio)</td>
			<td>BIO-RAD</td>
			<td>#1610147</td>
			<td>40% acrylamide/bis-acrylamide, 29:1 (3.3% crosslinker) solution for casting polyacrylamide gels</td>
		</tr>
		<tr>
			<td>&#196;KTA FPLC system</td>
			<td>GE Healthcare Life Sciences / Cytiva</td>
			<td>-</td>
			<td>using the FPLC system by GE Healthcare; different custom versions exist; this work used the &#34;&#196;KTA pure&#34; system</td>
		</tr>
		<tr>
			<td>Amicon Ultra-15, PLGC Ultracel-PL Membran, 10 kDa</td>
			<td>MERCK</td>
			<td>UFC901024</td>
			<td>centrifigal filters for protein enrichment; 10 kDa molecular mass filter; 15 mL</td>
		</tr>
		<tr>
			<td>Amicon Ultra-4, PLGC Ultracel-PL Membran, 10 kDa</td>
			<td>MERCK</td>
			<td>UFC801024</td>
			<td>centrifigal filters for protein enrichment; 10 kDa molecular mass filter; 4 mL</td>
		</tr>
		<tr>
			<td>Ammonium sulfate powder</td>
			<td>MERCK</td>
			<td>A4418</td>
			<td>ammonium sulphate for molecular biology, &#8805;99.0%</td>
		</tr>
		<tr>
			<td>Ammoniumpersulfat reagent grade, 98%</td>
			<td>MERCK</td>
			<td>215589</td>
			<td>Catalyst for acrylamide gel polymerization.</td>
		</tr>
		<tr>
			<td>Coomassie Brilliant blue R 250</td>
			<td>MERCK</td>
			<td>1125530025</td>
			<td>Coomassie Brilliant blue R 250 (C.I. 42660) for electrophoresis Trademark of Imperial Chemical Industries PLC. CAS 6104-59-2, pH 6.2 (10 g/l, H2O, 25 &#176;C)</td>
		</tr>
		<tr>
			<td>Dialysis tubing cellulose membrane</td>
			<td>MERCK</td>
			<td>D9277</td>
			<td>Cellulose membranes for the exchange of buffers via dialysis.</td>
		</tr>
		<tr>
			<td>Eppendof tubes 1.5 mL</td>
			<td>VWR</td>
			<td>525-1042</td>
			<td>microcentrifugal tubes; autoclaved</td>
		</tr>
		<tr>
			<td>HiLoad 26/600 Superdex 75 pg</td>
			<td>GE Healthcare Life Sciences / Cytiva</td>
			<td>28989334</td>
			<td>HiLoad Superdex 75 pg prepacked columns are for high-resolution size exclusion chromatography of recombinant proteins</td>
		</tr>
		<tr>
			<td>Immun-Blot PVDF Membrane</td>
			<td>BIO-RAD</td>
			<td>#1620177</td>
			<td>PVDF membranes are protein blotting membranes optimized for fluorescent and multiplex fluorescent applications.</td>
		</tr>
		<tr>
			<td>Mini Trans-Blot Electrophoretic Transfer Cell</td>
			<td>BIO-RAD</td>
			<td>#1703930</td>
			<td>Use the Mini Trans-Blot Cell for rapid blotting of Mini-PROTEAN precast and handcast gels.</td>
		</tr>
		<tr>
			<td>Mini-PROTEAN Tetra Vertical Electrophoresis Cell for Mini Precast Gels</td>
			<td>BIO-RAD</td>
			<td>#1658004</td>
			<td>4-gel vertical electrophoresis system, includes electrode assembly, companion running module, tank, lid with power cables, mini cell buffer dam.</td>
		</tr>
		<tr>
			<td>Mono Q 10/100 GL</td>
			<td>GE Healthcare Life Sciences / Cytiva</td>
			<td>17516701</td>
			<td>Mono Q columns are strong anion exchange chromatography columns for protein analysis or small scale, high resolution polishing of proteins.</td>
		</tr>
		<tr>
			<td>Mono S 10/100 GL</td>
			<td>GE Healthcare Life Sciences / Cytiva</td>
			<td>17516901</td>
			<td>Mono S columns are strong cation exchange chromatography columns for protein analysis or small scale high resolution polishing of proteins.</td>
		</tr>
		<tr>
			<td>PageRuler Prestained Protein Ladder, 10 to 180 kDa</td>
			<td>Thermo-Fischer</td>
			<td>26616</td>
			<td>A mixture of 10 blue-, orange-, and green-stained proteins (10 to 180 kDa) for use as size standards in protein electrophoresis (SDS-PAGE) and western blotting.</td>
		</tr>
		<tr>
			<td>Pierce BCA Protein Assay Kit</td>
			<td>Thermo-Fischer</td>
			<td>23225</td>
			<td>A two-component, high-precision, detergent-compatible protein assay for determination of protein concentration.</td>
		</tr>
		<tr>
			<td>Sonifier 250; Ultrasonic Cell Disruptor w/ Converter</td>
			<td>Branson</td>
			<td>-</td>
			<td>New models at https://www.emerson.com/documents/automation/brochure-sonifier-sfx250-sfx550-cell-disruptors-homogenizers-branson-en-us-168180.pdf</td>
		</tr>
		<tr>
			<td>Swine Anti-Rabbit Immunoglobulins/HRP (affinity isolated)</td>
			<td>Agilent Dako</td>
			<td>P0399</td>
			<td>The antibody used for horseradish peroxidase conjugation reacts with rabbit immunoglobulins of all classes.</td>
		</tr>
		<tr>
			<td>TEMED, 1,2-Bis(dimethylamino)ethane, TMEDA</td>
			<td>MERCK</td>
			<td>T9281</td>
			<td>TEMED (N,N,N&#8242;,N&#8242;-Tetramethylethylenediamine) is molecule which allows rapid polymerization of polyacrylamide gels.</td>
		</tr>
		<tr>
			<td>Tube Roller</td>
			<td>-</td>
			<td>-</td>
			<td>A general tube rotator roller; e.g. a new model at https://labstac.com/de/Mixer/Roller/c/71</td>
		</tr>
		<tr>
			<td>Tube Rotator</td>
			<td>-</td>
			<td>-</td>
			<td>A general tube rotator wheel; e.g. a new model at https://labstac.com/de/Tube-Roller/p/MT123</td>
		</tr>
		<tr>
			<td>ULTRA-TURRAX; T 25 digital</td>
			<td>IKA</td>
			<td>0003725000</td>
			<td>New models at https://www.ika.com/de/Produkte-Lab-Eq/Dispergierer-Dipergiergeraet-Homogenisierer-Homogenisator-csp-177/T-25-digital-ULTRA-TURRAX-cpdt-3725000/</td>
		</tr>
	</tbody>
</table>

extraction and purification of fahd1 protein from swine kidney and mouse liver

Fumarylacetoacetate hydrolase domain-containing protein 1 (FAHD1) is the first identified member of the FAH superfamily in eukaryotes, acting as oxaloacetate decarboxylase in mitochondria. This article presents a series of methods for the extraction and purification of FAHD1 from swine kidney and mouse liver. Covered methods are ionic exchange chromatography with fast protein liquid chromatography (FPLC), preparative and analytical gel filtration with FPLC, and proteomic approaches. After total protein extraction, ammonium sulfate precipitation and ionic exchange chromatography were explored, and FAHD1 was extracted via a sequential strategy using ionic exchange and size-exclusion chromatography. This representative approach may be adapted to other proteins of interest (expressed at significant levels) and modified for other tissues. Purified protein from tissue may support the development of high-quality antibodies, and/or potent and specific pharmacological inhibitors.

FAHD1 protein was extracted from swine kidney and mouse liver using the presented protocol. For mouse tissue, multiple organs are required to obtain several &#181;g after the final purification step. For this reason, this article focuses on the extraction of FAHD1 from swine kidneys, which is a much more exemplary experiment. The extraction of FAHD1 from the mouse liver is performed to present the difficulties and possible pitfalls of this protocol. It is generally recommended to use organs that show a high expression le...

Watch this Scientific Journal Video about Extraction and Purification of FAHD1 Protein from Swine Kidney and Mouse Liver at JoVE.com

Extraction and Purification of FAHD1 Protein from Swine Kidney and Mouse Liver

This protocol describes how to extract fumarylacetoacetate hydrolase domain-containing protein 1 (FAHD1) from swine kidney and mouse liver. The listed methods may be adapted to other proteins of interest and modified for other tissues.

Fumarylacetoacetate hydrolase domain-containing protein 1 (FAHD1) is the first identified member of the FAH superfamily in eukaryotes, acting as ...

extraction-purification-fahd1-protein-from-swine-kidney-mouse

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Biochemistry

4.6K Views.  University of Innsbruck. This protocol describes how to extract fumarylacetoacetate hydrolase domain-containing protein 1 (FAHD1) from swine kidney and mouse liver. The listed methods may be adapted to other proteins of interest and modified for other tissues.

Video: Extraction and Purification of FAHD1 Protein from Swine Kidney and Mouse Liver

Directed Protein Packaging within Outer Membrane Vesicles from Escherichia coli: Design, Production and Purification

An increasing interest in applying synthetic biology techniques to program outer membrane vesicles (OMV) are leading to some very interesting and unique applications for OMV where traditional nanoparticles are proving too difficult to synthesize. To date, all Gram-negative bacteria have been shown to produce OMV demonstrating packaging of a variety of cargo that includes small molecules, peptides, proteins and genetic material. Based on their diverse cargo, OMV are implicated in many biological processes ranging from cell-cell communication to gene transfer and delivery of virulence factors depending upon which bacteria are producing the OMV. Only recently have bacterial OMV become accessible for use across a wide range of applications through the development of techniques to control and direct packaging of recombinant proteins into OMV. This protocol describes a method for the production, purification, and use of enzyme packaged OMV providing for improved overall production of recombinant enzyme, increased vesiculation, and enhanced enzyme stability. Successful utilization of this protocol will result in the creation of a bacterial strain that simultaneously produces a recombinant protein and directs it for OMV encapsulation through creating a synthetic linkage between the recombinant protein and an outer membrane anchor protein. This protocol also details methods for isolating OMV from bacterial cultures as well as proper handling techniques and things to consider when adapting this protocol for use for other unique applications such as: pharmaceutical drug delivery, medical diagnostics, and environmental remediation.

Directed Protein Packaging within Outer Membrane Vesicles from Escherichia coli: Design, Production and Purification

A protocol for the production, purification, and use of enzyme packaged outer membrane vesicles (OMV) providing for enhanced enzyme stability for implementation across diverse applications is presented.

An increasing interest in applying synthetic biology techniques to program outer membrane vesicles (OMV) are leading to some very interesting and unique ...

Tandem Affinity Purification of Protein Complexes from Eukaryotic Cells

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo identification of novel subunits and post-translational modifications. Bacterial systems allow for the expression and purification of a wide variety of single polypeptides and protein complexes. However, this system does not enable the purification of protein subunits that contain post-translational modifications (e.g., phosphorylation and acetylation), and the identification of novel regulatory subunits that are only present/expressed in the eukaryotic system. Here, we provide a detailed description of a novel, robust, and efficient tandem affinity purification (TAP) method using STREP- and FLAG-tagged proteins that facilitates the purification of protein complexes with transiently or stably expressed epitope-tagged proteins from eukaryotic cells. This protocol can be applied to characterize protein complex functionality, to discover post-translational modifications on complex subunits, and to identify novel regulatory complex components by mass spectrometry. Notably, this TAP method can be applied to study protein complexes formed by eukaryotic or pathogenic (viral and bacterial) components, thus yielding a wide array of downstream experimental opportunities. We propose that researchers working with protein complexes could utilize this approach in many different ways.

We describe here a novel, robust, and efficient tandem affinity purification (TAP) method for the expression, isolation, and characterization of protein complexes from eukaryotic cells. This protocol could be utilized for the biochemical characterization of discrete complexes as well as the identification of novel interactors and post-translational modifications that regulate their function.

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo ...

Purification of Hepatocytes and Sinusoidal Endothelial Cells from Mouse Liver Perfusion

This protocol demonstrates a method for obtaining high yield and viability for mouse hepatocytes and sinusoidal endothelial cells (SECs) suitable for culturing or for obtaining cell lysates. In this protocol, the portal vein is used as the site for catheterization, rather than the vena cava, as this limits contamination of other possible cell types in the final liver preparation. No special instrumentation is required throughout the procedure. A water bath is used as a source of heat to maintain the temperature of all the buffers and solutions. A standard peristaltic pump is used to drive the fluid, and a refrigerated table-top centrifuge is required for the centrifugation procedures. The only limitation of this technique is the placement of the catheter within the portal vein, which is challenging on some of the mice in the 18 - 25 g size range. An advantage of this technique is that only one vein is utilized for the perfusion and the access to the vein is quick, which minimizes ischemia and reperfusion of the liver that reduces hepatic cell viability. Another advantage to this protocol is that it is easy to distinguish live from dead hepatocytes by eyesight due to the difference in cellular density during the centrifugation steps. Cells from this protocol may be used in cell culture for any downstream application as well as processed for any biochemical assessment.

The goal of this protocol is to obtain high viability and high yield of hepatocytes and sinusoidal endothelial cells from liver. This is accomplished by perfusing the liver with a type IV collagenase solution via the portal vein, followed by differential centrifugation to obtain hepatocytes and sinusoidal endothelial cells.

This protocol demonstrates a method for obtaining high yield and viability for mouse hepatocytes and sinusoidal endothelial cells (SECs) suitable for ...

2 in 1: One-step Affinity Purification for the Parallel Analysis of Protein-Protein and Protein-Metabolite Complexes

Cellular processes are regulated by interactions between biological molecules such as proteins, metabolites, and nucleic acids. While the investigation of protein-protein interactions (PPI) is no novelty, experimental approaches aiming to characterize endogenous protein-metabolite interactions (PMI) constitute a rather recent development. Herein, we present a protocol that allows simultaneous characterization of the PPI and PMI of a protein of choice, referred to as bait. Our protocol was optimized for Arabidopsis cell cultures and combines affinity purification (AP) with mass spectrometry (MS)-based protein and metabolite detection. In short, transgenic Arabidopsis lines, expressing bait protein fused to an affinity tag, are first lysed to obtain a native cellular extract. Anti-tag antibodies are used to pull down protein and metabolite partners of the bait protein. The affinity-purified complexes are extracted using a one-step methyl tert-butyl ether (MTBE)/methanol/water method. Whilst metabolites separate into either the polar or the hydrophobic phase, proteins can be found in the pellet. Both metabolites and proteins are then analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS or UPLC-MS/MS). Empty-vector (EV) control lines are used to exclude false positives. The major advantage of our protocol is that it enables identification of protein and metabolite partners of a target protein in parallel in near-physiological conditions (cellular lysate). The presented method is straightforward, fast, and can be easily adapted to biological systems other than plant cell cultures.

Protein-protein and protein-metabolite interactions are crucial for all cellular functions. Herein, we describe a protocol that allows parallel analysis of these interactions with a protein of choice. Our protocol was optimized for plant cell cultures and combines affinity purification with mass spectrometry-based protein and metabolite detection.

Cellular processes are regulated by interactions between biological molecules such as proteins, metabolites, and nucleic acids. While the investigation of ...

Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition

Oxygen-sensitive proteins, including those enzymes which utilize oxygen as a substrate, can have reduced stability when purified using traditional aerobic purification methods. This manuscript illustrates the technical details involved in the anaerobic purification process, including the preparation of buffers and reagents, the methods for column chromatography in a glove box, and the desalting of the protein prior to kinetics. Also described are the methods for preparing and using an oxygen electrode to perform kinetic characterization of an oxygen-utilizing enzyme. These methods are illustrated using the dioxygenase enzyme DesB, a gallate dioxygenase from the bacterium Sphingobium sp. strain SYK-6.

Here we present a protocol for anaerobic protein purification, anaerobic protein concentration, and subsequent kinetic characterization using an oxygen electrode system. The method is illustrated using the enzyme DesB, a dioxygenase enzyme which is more stable and active when purified and stored in an anaerobic environment.

Oxygen-sensitive proteins, including those enzymes which utilize oxygen as a substrate, can have reduced stability when purified using traditional aerobic ...

Ganglioside Extraction, Purification and Profiling

Gangliosides are glycosphingolipids that contain one or more sialic acid residues. They are found on all vertebrate cells and tissues but are especially abundant in the brain. Expressed primarily on the outer leaflet of the plasma membranes of cells, they modulate the activities of cell surface proteins via lateral association, act as receptors in cell-cell interactions and are targets for pathogens and toxins. Genetic dysregulation of ganglioside biosynthesis in humans results in severe congenital nervous system disorders. Because of their amphipathic nature, extraction, purification, and analysis of gangliosides require techniques that have been optimized by many investigators in the 80 years since their discovery. Here, we describe bench-level methods for the extraction, purification, and preliminary qualitative and quantitative analyses of major gangliosides from tissues and cells that can be completed in a few hours. We also describe methods for larger scale isolation and purification of major ganglioside species from brain. Together, these methods provide analytical and preparative scale access to this class of bioactive molecules.

Gangliosides are sialic acid-bearing glycosphingolipids that are particularly abundant in the brain. Their amphipathic nature requires organic/aqueous extraction and purification techniques to ensure optimal recovery and accurate analyses. This article provides overviews of analytic and preparative scale ganglioside extraction, purification, and thin layer chromatography analysis.

Gangliosides are glycosphingolipids that contain one or more sialic acid residues. They are found on all vertebrate cells and tissues but are especially ...

Extraction and Visualization of Protein Aggregates after Treatment of Escherichia coli with a Proteotoxic Stressor

The exposure of living organisms to environmental and cellular stresses often causes disruptions in protein homeostasis and can result in protein aggregation. The accumulation of protein aggregates in bacterial cells can lead to significant alterations in the cellular phenotypic behavior, including a reduction in growth rates, stress resistance, and virulence. Several experimental procedures exist for the examination of these stressor-mediated phenotypes. This paper describes an optimized assay for the extraction and visualization of aggregated and soluble proteins from different Escherichia coli strains after treatment with a silver-ruthenium-containing antimicrobial. This compound is known to generate reactive oxygen species and causes widespread protein aggregation. 
The method combines a centrifugation-based separation of protein aggregates and soluble proteins from treated and untreated cells with subsequent separation and visualization by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Coomassie staining. This approach is simple, fast, and allows a qualitative comparison of protein aggregate formation in different E. coli strains. The methodology has a wide range of applications, including the possibility to investigate the impact of other proteotoxic antimicrobials on in vivo protein aggregation in a wide range of bacteria. Moreover, the protocol can be used to identify genes that contribute to increased resistance to proteotoxic substances. Gel bands can be used for the subsequent identification of proteins that are particularly prone to aggregation.

Extraction and Visualization of Protein Aggregates after Treatment of Escherichia coli with a Proteotoxic Stressor

This protocol describes the extraction and visualization of aggregated and soluble proteins from Escherichia coli after treatment with a proteotoxic antimicrobial. Following this procedure allows a qualitative comparison of protein aggregate formation in vivo in different bacterial strains and/or between treatments.

The exposure of living organisms to environmental and cellular stresses often causes disruptions in protein homeostasis and can result in protein ...

The Extraction of Liver Glycogen Molecules for Glycogen Structure Determination

Liver glycogen is a hyperbranched glucose polymer that is involved in the maintenance of blood sugar levels in animals. The properties of glycogen are influenced by its structure. Hence, a suitable extraction method that isolates representative samples of glycogen is crucial to the study of this macromolecule. Compared to other extraction methods, a method that employs a sucrose density gradient centrifugation step can minimize molecular damage. Based on this method, a recent publication describes how the density of the sucrose solution used during centrifugation was varied (30%, 50%, 72.5%) to find the most suitable concentration to extract glycogen particles of a wide variety of sizes, limiting the loss of smaller particles. A 10 min boiling step was introduced to test its ability to denature glycogen degrading enzymes, thus preserving glycogen. The lowest sucrose concentration (30%) and the addition of the boiling step were shown to extract the most representative samples of glycogen.

An optimal sucrose concentration was determined for the extraction of liver glycogen using sucrose density gradient centrifugation. The addition of a 10 min boiling step to inhibit glycogen-degrading enzymes proved beneficial.

Liver glycogen is a hyperbranched glucose polymer that is involved in the maintenance of blood sugar levels in animals. The properties of glycogen are ...

Exploring Biomolecular Interaction Between the Molecular Chaperone Hsp90 and Its Client Protein Kinase Cdc37 using Field-Effect Biosensing Technology

Biomolecular interactions play versatile roles in numerous cellular processes&#160;by regulating and coordinating functionally relevant biological events. Biomolecules such as proteins, carbohydrates, vitamins, fatty acids, nucleic acids, and enzymes are fundamental building blocks of living beings; they assemble into complex networks in biosystems to synchronize a myriad of life events. Proteins typically utilize complex interactome networks to carry out their functions; hence it is mandatory to evaluate such interactions to unravel their importance in cells at both cellular and organism levels. Toward this goal, we introduce a rapidly emerging technology, field-effect biosensing (FEB), to determine specific biomolecular interactions. FEB is a benchtop, label-free, and reliable biomolecular detection technique to determine specific interactions and uses high-quality electronic-based biosensors. The FEB technology can monitor interactions in the nanomolar range due to the biocompatible nanomaterials used on its biosensor surface. As a proof of concept, the protein-protein interaction (PPI) between heat shock protein 90 (Hsp90) and cell division cycle 37 (Cdc37) was elucidated. Hsp90 is an ATP-dependent molecular chaperone that plays an essential role in the folding, stability, maturation, and quality control of many proteins, thereby regulating multiple vital cellular functions. Cdc37 is regarded as a protein kinase-specific molecular chaperone, as it specifically recognizes and recruits protein kinases to Hsp90 to regulate their downstream signal transduction pathways. As such, Cdc37 is considered a co-chaperone of Hsp90. The chaperone-kinase pathway (Hsp90/Cdc37 complex) is hyper-activated in multiple malignancies promoting cellular growth; therefore, it is a potential target for cancer therapy. The present study demonstrates the efficiency of FEB technology using the Hsp90/Cdc37 model system. FEB detected a strong PPI between the two proteins (KD values of 0.014 &#181;M, 0.053 &#181;M, and 0.072 &#181;M in three independent experiments). In summary, FEB is a label-free and cost-effective PPI detection platform, which offers fast and accurate measurements.

Field-effect biosensing (FEB) is a label-free technique for detecting biomolecular interactions. It measures the electric current through the graphene biosensor to which the binding targets are immobilized. The FEB technology was used to evaluate biomolecular interactions between Hsp90 and Cdc37 and a strong interaction between the two proteins was detected.

Biomolecular interactions play versatile roles in numerous cellular processes&#160;by regulating and coordinating functionally relevant biological events. ...

Purifying a Fibrinolytic Enzyme from Sipunculus nudus via Affinity Chromatography

Affinity Purification of a Fibrinolytic Enzyme from Sipunculus nudus

The fibrinolytic enzyme from Sipunculus nudus (sFE) is a novel fibrinolytic agent that can both activate plasminogen into plasmin and degrade fibrin directly, showing great advantages over traditional thrombolytic agents. However, due to the lack of structural information, all the purification programs for sFE are based on multistep chromatography purifications, which are too complicated and costly. Here, an affinity purification protocol of sFE is developed for the first time based on a crystal structure of sFE; it includes preparation of the crude sample and the lysine/arginine-agarose matrix affinity chromatography column, affinity purification, and characterization of the purified sFE. Following this protocol, a batch of sFE can be purified within 1 day. Moreover, the purity and activity of the purified sFE increases to 92% and&#160;19,200 U/mL,&#160;respectively. Thus, this is a simple, inexpensive, and efficient approach for sFE purification. The development of this protocol is of great significance for the further utilization of sFE and other similar agents.

Author Spotlight: Affinity Purification of a Fibrinolytic Enzyme from Sipunculus nudus  

Here, we present an affinity purification method of a fibrinolytic enzyme from Sipunculus nudus that is simple, inexpensive, and efficient.

The fibrinolytic enzyme from Sipunculus nudus (sFE) is a novel fibrinolytic agent that can both activate plasminogen into plasmin and degrade fibrin ...