胆碱脱氢酶的动力学性质  

Kinetic Properties of Choline Dehydrogenase

作　　者：傅晓红[1] 林其谁[1] 

机构地区：[1]中国科学院上海生物化学研究所分子生物学国家重点实验室

出　　处：《生物化学与生物物理学报》1997年第2期170-175,共6页

摘　　要：本文对增溶胆碱脱氢酶的稳态初速度及产物抑制动力学做了研究。底物胆碱和ＰＭＳ的相互影响为：变化一个底物的浓度，另一个底物的Ｋｍ及Ｖｍａｘ均变化。该酶的产物三甲胺乙醛对酶的抑制表现为对底物胆碱非竞争性而对ＰＭＳ竞争性，在胆碱饱和的情况下，三甲胺乙醛对酶的抑制仍表现为对ＰＭＳ竞争性。这些结果表明增溶胆碱脱氢酶的催化机制为双底物双产物乒乓机制。１－ＰＣ（１－ｐｙｒｅｎｅｂｕｔｙｒｙｌｃｈｏｌｉｎｅｂｒｏｍｉｄｅ）与９－ＡＣ（９－ａｎｔｈｒｏｌｃｈｏｌｉｎｅｂｒｏｍｉｄｅ）对增溶胆碱脱氢酶均有抑制作用，且均为混和型抑制，Ｋｉ分别为０．３ｍｍｏｌ／Ｌ、３．６７ｍｍｏｌ／Ｌ。The kinetic behavior of purified CDH had been investigated by steady state initial velocity studies and inhibition studies with products. Variations in the concentration of one substrate led to changes in the K m and V max for the other substrate. The product betaine aldehyde was a noncompetitive inhibitor with respect to choline, whereas it competed with PMS. The results were consistent with a Bi Bi Ping Pong mechanism. 1 PC (1 pyrenebutyrylcholine bromide) and 9 AC (9 anthrolcholine bromide) behaved as mixed inhibitors, with K i values of 0.3 mM and 3.67 mM respectively.

关 键 词：胆碱脱氢酶 性质 动力学 

分 类 号：Q556.02[生物学—生物化学]