三磷酸腺苷（ATP）对电鳗（Electrophorus electricus (L.)）电器官中纯化的L(+)乳酸脱氢酶的影响。

Effect of ATP on purified L(+) lactate dehydrogenase from electric organ of Electrophorus electricus (L.).

作者信息

Torres-da Matta J, Batista e Silva C, Hassón-Voloch A

出版信息

Int J Biochem. 1986;18(2):191-4. doi: 10.1016/0020-711x(86)90156-4.

Abstract

L(+) lactate dehydrogenase (LDH) activity from the electric organ of Electrophorus electricus was measured in the presence of ATP in the forward (substrate lactate) and reverse (substrate pyruvate) enzymatic reactions. The I50 for ATP was first determined and then the kinetics of the reactions were investigated with either constant coenzyme (NAD or NADH) concentration and varying substrate (lactate or pyruvate) concentration, or, constant substrate and varying coenzyme concentration. The kinetic data showed that ATP inhibits LDH uncompetitively with respect to the reduced and the oxidized coenzyme. As for the substrates, ATP gives a mixed type inhibition for lactate and a noncompetitive inhibition for pyruvate.

摘要

在正向（底物为乳酸）和反向（底物为丙酮酸）酶促反应中，于ATP存在的情况下，测定了电鳗发电器官中的L(+)乳酸脱氢酶（LDH）活性。首先确定了ATP的半数抑制浓度（I50），然后在辅酶（NAD或NADH）浓度恒定而底物（乳酸或丙酮酸）浓度变化，或者底物恒定而辅酶浓度变化的条件下，研究了反应动力学。动力学数据表明，ATP对还原型和氧化型辅酶而言，对LDH产生非竞争性抑制作用。至于底物，ATP对乳酸产生混合型抑制作用，对丙酮酸产生非竞争性抑制作用。