Nemerya N S, Khailova L S, Severin S E
Biochem Int. 1984 Mar;8(3):369-76.
The pyruvate dehydrogenase component isolated from the pigeon breast muscle pyruvate dehydrogenase complex is inactivated by the arginine-specific reagents, 2,3-butanedione and phenylglyoxal. The kinetics of inactivation is biphasic. The reaction order with respect to the inhibitor concentration at the fast and slow steps of the inactivation reaction is close to unity. This suggests that complete inactivation of the enzyme results from the interaction of two molecules of 2,3-butanedione or phenylglyoxal with essential groups of pyruvate dehydrogenase. In the presence of thiamine pyrophosphate and Mg2+ pyruvate protects the enzyme against inactivation. The experimental results are suggestive of the presence of two arginine residues in the substrate-binding sites of two active centres of the holoenzyme.
从鸽胸肌丙酮酸脱氢酶复合体中分离出的丙酮酸脱氢酶组分可被精氨酸特异性试剂2,3-丁二酮和苯乙二醛灭活。失活动力学是双相的。在失活反应的快速和慢速阶段，相对于抑制剂浓度的反应级数接近1。这表明酶的完全失活是由于两分子的2,3-丁二酮或苯乙二醛与丙酮酸脱氢酶的必需基团相互作用所致。在硫胺素焦磷酸和Mg2+存在的情况下，丙酮酸可保护该酶不被灭活。实验结果提示全酶的两个活性中心的底物结合位点中存在两个精氨酸残基。
