title: A rapid purification procedure for camel kidney glutathione S-transferase.
abstract: Glutathione S-transferase was isolated from supernatant of camel kidney homogenate centrifugation at 37,000 xg by glutathione agarose affinity chromatography. The enzyme preparation has a specific activity of 44 mumol/min/mg protein and recovery was more than 85% of the enzyme activity in the crude extract. Glutathione agarose affinity chromatography resulted in a purification factor of about 49 and chromatofocusing resolved the purified enzyme into two major isoenzymes (pI 8.7 and 7.9) and two minor isoenzymes (pI 8.3 and 6.9). The homogeneity of the purified enzyme was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration on Sephadex G-100. The different isoenzymes were composed of a binary combination of two subunits with molecular weight of 29,000 D and 26,000 D to give a native molecular weight of 55,000 D. The substrate specificities of the major camel kidney glutathione S-transferase isoenzymes were determined towards a range of substrates. 1-chloro-2,4-dinitrobenzene was the preferred substrate for all the isoenzymes. Isoenzyme III (pI 7.9) had higher specific activity for ethacrynic acid and isoenzyme II (pI 8.3) was the only isoenzyme that exhibited peroxidase activity. Ouchterlony double-diffusion analysis with rabbit antiserum prepared against the camel kidney enzyme showed fusion of precipitation lines with the enzymes from camel brain, liver and lung and no cross reactivity was observed with enzymes from kidneys of sheep, cow, rat, rabbit and mouse. Different storage conditions have been found to affect the enzyme activity and the loss in activity was marked at room temperature and upon repeated freezing and thawing.
mesh_terms: D000818:Animals; D002162:Camelus / Q000378:metabolism*; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D005982:Glutathione Transferase / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D005779:Immunodiffusion; D007163:Immunosorbent Techniques; D007527:Isoenzymes / Q000302:isolation & purification; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D005982:Glutathione Transferase