Ionic Strength and pH Effects on the Rates of Reduction of Spinach Plastocyanin by Ascorbate1
- 1 January 1980
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 87 (1), 111-115
- https://doi.org/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°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 electrontransfer reaction. The importance of electrostatic interactions between plastocyanin and ascorbate is discussed in relation to the photosynthetic electron-transport reactions.Keywords
This publication has 8 references indexed in Scilit:
- Kinetic Studies on 1:1 Electron-Transfer Reactions Involving Blue Copper Proteins. 1. Evidence for an Unreactive Form of the Reduced Protein (pH<5) and for Protein-Complex Association in Reactions of Parsley (and Spinach) PlastocyaninJournal of the American Chemical Society, 1978
- Protein-protein electron transfer. A Marcus theory analysis of reactions between c type cytochromes and blue copper proteinsBiochemistry, 1978
- Electron-transfer protein reactivities. Kinetic studies of the oxidation of horse heart cytochrome c, Chromatium vinosum high potential iron-sulfur protein, Pseudomonas aeruginosa azurin, bean plastocyanin, and Rhus vernicifera stellacyanin by pentaammminepyridineruthenium(III)Journal of the American Chemical Society, 1977
- Chloroplast membrane sidedness. Location of plastocyanin determined by chemical modifiersBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1977
- Ionic strength and pH effects on the rates of reduction of blue copper proteins by iron(EDTA)2-. Comparison of the reactivities of Pseudomonas aeruginosa azurin and bean plastocyanin with various redox agentsJournal of the American Chemical Society, 1976
- The presence of glutathione and glutathione reductase in chloroplasts: A proposed role in ascorbic acid metabolismPlanta, 1976
- Kinetics of the cupric salt-catalysed autoxidation of -ascorbic acid in aqueous solutionsTetrahedron, 1968
- The ionization of acidic metmyoglobin. Ionic-strength charge effectsBiochemical Journal, 1957