离子强度和pH值对抗坏血酸还原菠菜质体蓝素速率的影响。

Ionic strength and pH effects on the rates of reduction of spinach plastocyanin by ascorbate.

作者信息

Takabe T, Niwa S, Ishikawa H, Miyakawa M

出版信息

J Biochem. 1980 Jan;87(1):111-5. doi: 10.1093/oxfordjournals.jbchem.a132715.

DOI:10.1093/oxfordjournals.jbchem.a132715

Abstract

Kinetic studies of the reduction of plastocyanin from spinach chloroplasts by ascorbate were carried out using a stopped flow apparatus. The reduction of spinach plastocyanin by ascorbate followed first-order kinetics in the reductant with a rate constant k = 415 M-1.S-1 [20 degrees C, 0.1 M NaCl, pH 8.0 (10 mM Tris-HCl)]. The second-order rate constants for the reduction of plastocyanin by ascorbate increased dramatically with increasing pH and ionic strength. The cationic micelles of cetyltrimethylammonium bromide also accelerated this electron-transfer reaction. The importance of electrostatic interactions between plastocyanin and ascorbate is discussed in relation to the photosynthetic electron-transport reactions.

摘要

使用停流装置对菠菜叶绿体中的质体蓝素被抗坏血酸还原进行了动力学研究。抗坏血酸对菠菜质体蓝素的还原在还原剂中遵循一级动力学，速率常数k = 415 M-1·S-1 [20℃，0.1 M NaCl，pH 8.0（10 mM Tris-HCl）]。抗坏血酸还原质体蓝素的二级速率常数随着pH值和离子强度的增加而显著增加。十六烷基三甲基溴化铵的阳离子胶束也加速了这种电子转移反应。结合光合电子传递反应讨论了质体蓝素和抗坏血酸之间静电相互作用的重要性。