Javed M U, Waqar M A
Department of Biochemistry, Aga Khan University, Karachi, Pakistan.
J Enzyme Inhib. 1996;10(3):187-93. doi: 10.3109/14756369609030312.
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.
从麻蜥睾丸中纯化出一种乳酸脱氢酶同工酶并使其达到同质，同时研究了其对已知乳酸脱氢酶同工酶抑制剂的抑制谱。铂化合物仅在正向反应（丙酮酸→乳酸）中抑制该酶，正己二醇和秋水仙碱无抑制作用，而棉酚乙酸（GAA）强烈抑制正向和反向反应，且反应呈时间依赖性。草酸盐对正向反应产生非竞争性抑制（表观抑制常数Ki =半数抑制浓度IC50 = 0.15 mM），烟酰胺腺嘌呤二核苷酸（NADH）比丙酮酸更有效地阻断GAA的抑制作用。这种酶也不能将酮己酸用作底物。
