Partial Resolution of the Enzymes Catalyzing Photophosphorylation

作者：Richard E. McCarty, Efraim Racker · 发表于：Journal of Biological Chemistry · 年份：1967 · DOI：10.1016/s0021-9258(18)95881-3 · 被引用次数：248 · 研究领域：Photosynthetic Processes and Mechanisms、Light effects on plants、Mitochondrial Function and Pathology

Dicyclohexylcarbodiimide inhibited electron transport in chloroplasts. This inhibition was reversed by ammonia but not by a phosphate acceptor system. In the presence of an uncoupler such as ammonia, the inhibition by dicyclohexylcarbodiimide was only about 50%. Dicyclohexylcarbodiimide inhibited phosphorylation associated with ferricyanide reduction in coupled chloroplasts. The extent of inhibition of reduction and phosphorylation was about equal except at high concentrations of dicyclohexylcarbodiimide, which inhibited phosphorylation more severely. Dicyclohexylcarbodiimide had no effect on the light-induced pH rise in coupled chloroplasts, but markedly stimulated this reaction in ethylenediaminetetraacetate-treated chloroplasts which were partially deficient in coupling factor 1. The rate of pH decay in the ethylenediaminetetraacetate-treated chloroplasts was several times higher than that in the coupled chloroplasts. Dicyclohexylcarbodiimide inhibited the pH decay, indicating that its stimulation of the light-induced pH rise might be due to an inhibition of the breakdown of a high energy intermediate in chloroplasts. Low concentrations of dicyclohexylcarbodiimide markedly stimulated photophosphorylation in ethylenediaminetetraacetate-treated chloroplasts. Maximal rates of phosphorylation were observed only in the presence of dicyclohexylcarbodiimide and the coupling factor. The antiserum to the coupling factor inhibited the phosphorylation stimulated by dicyclohexylcarbod...