法国菜豆（Phaseolus vulgaris）绿叶和黄化子叶中的甲羟戊酸激酶

Mevalonate kinase in green leaves and etiolated cotyledons of the french bean Phaseolus vulgaris.

Gray J C, Kekwick R G

Biochem J. 1973 Jun;133(2):335-47. doi: 10.1042/bj1330335.

Abstract

Partially purified preparations of mevalonate kinase were obtained from green leaves and etiolated cotyledons of Phaseolus vulgaris. 2. After removal of interfering polyphenols both enzyme preparations behaved identically on gel filtration, ion-exchange chromatography and density-gradient centrifugation. 3. The kinetic parameters of the preparations from the two sources were indistinguishable. The preparation from etiolated cotyledons had a K(m) of 4.26x10(-5)m for RS-mevalonate and 1.54x10(-3)m for ATP. The preparation from green leaves had a K(m) of 4.55x10(-5)m for RS-mevalonate and 1.75x10(-3)m for ATP. The pH optimum of both enzyme preparations was pH7.0. 4. The effect of inhibitors on the two enzyme preparations was similar, both being inhibited by reagents known to react with thiol groups, and the two preparations had similar inhibitor constants for competitive inhibition by prenyl pyrophosphates. 5. The molecular weight of the enzyme in both preparations was estimated to be 100000; the enzymes from the two preparations had similar mobilities on polyacrylamide-gel electrophoresis.

摘要

从菜豆的绿叶和黄化子叶中获得了部分纯化的甲羟戊酸激酶制剂。2. 去除干扰性多酚后，两种酶制剂在凝胶过滤、离子交换色谱和密度梯度离心中的表现相同。3. 两种来源的制剂的动力学参数无法区分。黄化子叶的制剂对RS-甲羟戊酸的K(m)为4.26×10(-5)m，对ATP的K(m)为1.54×10(-3)m。绿叶的制剂对RS-甲羟戊酸的K(m)为4.55×10(-5)m，对ATP的K(m)为1.75×10(-3)m。两种酶制剂的最适pH均为pH7.0。4. 抑制剂对两种酶制剂的作用相似，二者均被已知与巯基反应的试剂抑制，且两种制剂对异戊烯基焦磷酸竞争性抑制的抑制常数相似。5. 两种制剂中酶的分子量估计为100000；两种制剂的酶在聚丙烯酰胺凝胶电泳上具有相似的迁移率。