Some properties of shikimate : NADP oxidoreductase produced in sweet potato root tissue after slicing

概要

論文の詳細を見る
The activity of shikimate: NADP oxidoreductase [EC 1. 1. 1. 25] in sweet potato root tissue increased soon after slicing. Enzyme preparations obtained from both sliced tissue and from fresh tissue probably contained a single enzyme component, and they showed identical chromatographical behaviour. K_m values of the enzyme for NADP and shikimate were 1.0×10^<-4>M and 1.3×10^<-3>M respectively. Enzyme activity was potently inhibited by SH-inhibitors such as p-chloromercuribenzoate and oxidized glutathione. Enzyme activity was affected neither by mononucleotides such as ATP. ADP and AMP, divalent cations, Mg^<++>, Ca^<++> and Mn^<++>, nor by metabolites such as tryptophan, phenylalanine, tyrosine and t-cinnamic acid which are involved in aromatic compound syntheses. The enzyme rapidly lost its activity. This inactivation reaction showed a time course consisting of two steps of the first-order reaction. The inactivated enzyme preparation was not reactivated by thiol compounds such as cysteine, 2-mercaptoethanol and glutathione, although these reagents, to a certain extent, protected the enzyme from inactivation. The results suggest that denaturation of the enzyme protein was involved in inactivation of the enzyme.
日本植物生理学会の論文