克氏锥虫胞质NADP - 苹果酸酶II的滞后现象。

Hysteresis of cytosolic NADP-malic enzyme II from Trypanosoma cruzi.

作者信息

Avilán L, García P

机构信息

Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela.

出版信息

Mol Biochem Parasitol. 1994 Jun;65(2):225-32. doi: 10.1016/0166-6851(94)90074-4.

DOI:10.1016/0166-6851(94)90074-4

PMID:7969264

Abstract

NADP-malic enzyme II, one of two isoenzymes of NADP-malic enzyme (EC 1.1.1.40) in Trypanosoma cruzi epimastigotes, presents hysteretic behavior that results in a kinetic lag in the reaction progress curve. The lag is affected by the malate, aspartate and oxaloacetate concentrations in the assay mixture. This dependence suggests that hysteresis is due to an association-dissociation process influenced by the binding of these ligands to the enzyme. The enzyme was separated from NADP-malic enzyme I and purified 43-fold from a cell homogenate by a procedure involving column chromatography on DEAE-Sephacel and Cibacron-blue Sepharose. The molecular mass of the highly purified enzyme was determined as 126 kDa.

摘要

NADP-苹果酸酶II是克氏锥虫前鞭毛体中NADP-苹果酸酶（EC 1.1.1.40）的两种同工酶之一，呈现滞后行为，这导致反应进程曲线出现动力学滞后。该滞后受测定混合物中苹果酸、天冬氨酸和草酰乙酸浓度的影响。这种依赖性表明滞后是由于这些配体与酶结合所影响的缔合-解离过程所致。通过涉及DEAE-琼脂糖凝胶和Cibacron蓝琼脂糖凝胶柱色谱的程序，将该酶与NADP-苹果酸酶I分离，并从细胞匀浆中纯化了43倍。高度纯化的酶的分子量测定为126 kDa。