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700542 
Journal Article 
Isolation from rat kidney of a cytosolic high molecular weight cysteine-S-conjugate beta-lyase with activity toward leukotriene E4 
Abraham, D; Patel, P; Cooper, A 
1995 
Yes 
Journal of Biological Chemistry
ISSN: 0021-9258
EISSN: 1083-351X 
270 
180-188 
English 
A cytosolic high M(r) cysteine-S-conjugate beta-lyase (apparent M(r) of approximately 330,000) has been partially purified from rat kidneys. The high M(r) lyase is also present in the mitochondria. The purified enzyme contains at least two proteins with apparent M(r) values of approximately 50,000 and approximately 70,000. Activity is stimulated by dithiothreitol, alpha-keto acids, and pyridoxal 5'-phosphate; aminooxyacetate is an inhibitor. The enzyme catalyzes a competing (half) transamination reaction between pyridoxal 5'-phosphate cofactor and cysteine-S-conjugate substrate; added alpha-keto acids promote conversion of active site pyridoxamine 5'-phosphate to pyridoxal 5'-phosphate. The enzyme also catalyzes a full (but weak) transamination between L-phenylalanine and alpha-keto-gamma-methiolbutyrate. The purified enzyme is not recognized by polyclonal rabbit antibodies to cytosolic rat kidney glutamine transaminase K (another cysteine-S-conjugate beta-lyase of rat kidney) and has no obvious similarities to other pyridoxal 5'-phosphate-containing enzymes. In addition to catalyzing elimination reactions with S-(1,2-dichlorovinyl)-L-cysteine and S-(1,1,2,2-tetrafluoroethyl)-L-cysteine, the enzyme reacts with leukotriene E4 and 5'-S-cysteinyldopamine. Finally, the cytosolic and mitochondrial enzymes are activated by alpha-ketoglutarate. Thus, the possibility must be considered that, in kidneys of animals exposed to various cysteine conjugates, the high M(r) lyase contributes to the generation of pyruvate, ammonia, and reactive fragments in vivo. Many cysteine conjugates are nephrotoxic, and the high M(r) lyase(s) may be involved. 
Animals 
Blotting, Western 
Chromatography, Ion Exchange 
Cysteine 
Cytosol 
Dopamine 
Electrophoresis, Polyacrylamide Gel 
Kidney 
Leukotriene E4 
Lyases 
Molecular Weight 
Rats 
Subcellular Fractions 
Transaminases