L-扁桃体酸脱氢酶的电化学特性

应用电化学方法研究了基础工程酶（L-扁桃体酸脱氢酶）的电化学性质，探讨了其催化机理。以聚赖氨酸为促进剂，L-扁桃体酸脱氢酶黄素微区在裂解石墨棱面（EPG，edge-palne pyrolytic praphite)电极上有两对氧化还原峰（-0.481V和-0.605V vs.SCE，Tris缓冲溶液pH7.5，扫描速度20mV/s），显示出酶的辅基黄素单核苷酸（FMN）与电极之间的电子传递过程。在此条件，L-扁桃体酸脱氢酶黄素微区不能催化L-扁桃体酸脱氢，但用二茂铁甲酸和细胞色素C作为媒介体，能促进酶催化反应有效地进行。

Electrochemical Property of L-Mandalate Dehydrogenase

The direct electrochemistry of flavodehydrogenase domain (FDH),an genetically engineered enzyme, has been investigated at edge plane pyrolytic graphite (EPG) electrode using poly L lysine as a promoter. Two redox couples (-0.481 V and -0.605 V vs SCE in the tris buffer solution at pH 7.5, scan rate 20 mV/s) were obtained on the cyclic voltammogram which respond to the separated two peaks in one electron reduction reoxidation steps of enzyme bounded flavin mononucleotide (FMN). The electrochemical transformation of the substrate L mandelic acid (LMA), catalysed by the FMN fragment of L mandalate dehydrogenase (LMDH) is inhibited at bare or promoter modified EPG, but both ferrocenemonocarboxylic acid (FMCA) and cytochrome C, function as mediators.