title: Inhibition studies on LDH isoenzyme purified from Uromastix testes.
abstract: An LDH isoenzyme was purified to homogeneity from uromastix testes and its inhibition spectrum towards known LDH isoenzyme inhibitors studied. Platinum compounds inhibited the enzyme in the forward reaction (pyruvate-->lactate) only, n-hexanediol and colchicine showed no inhibition and gossypol acetic acid (GAA) strongly inhibited both the forward and reverse reactions and the reactions were time-dependent. Oxalate caused non-competitive inhibition (Ki app = IC50 = 0.15 mM) of the forward reaction, NADH was more effective in blocking inhibition by GAA than pyruvate. This enzyme was also unable to use ketocaproic acid as a substrate.
authors.affiliation: Department of Biochemistry, Aga Khan University, Karachi, Pakistan.
authors.forename: M U
authors.initials: MU
authors.lastname: Javed
authors.forename: M A
authors.initials: MA
authors.lastname: Waqar
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002208:Caproates / Q000494:pharmacology; D002945:Cisplatin / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006072:Gossypol / Q000031:analogs & derivatives / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D008116:Lizards; D008297:Male; D009243:NAD / Q000378:metabolism; D010070:Oxalates / Q000494:pharmacology; D019815:Oxalic Acid; D019289:Pyruvic Acid / Q000378:metabolism; D013737:Testis / Q000201:enzymology*
chemical_list: D000970:Antineoplastic Agents; D002208:Caproates; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D010070:Oxalates; D009243:NAD; C001916:alpha-ketocaproic acid; D019289:Pyruvic Acid; D019815:Oxalic Acid; D007770:L-Lactate Dehydrogenase; D006072:Gossypol; D002945:Cisplatin; C028178:gossypol acetic acid