Uncouplers of Spinach Chloroplast Photosynthetic Phosphorylation.

Abstract

The criteria are indicated which identify a compound as an uncoupler of electron transport from phosphorylation in the phosphorylating Hill reaction. By these criteria, dinitrophenol and pentachlorophenol do not act as uncouplers in chloroplasts. Dilution of chloroplasts in NaCl at pH 6 results in uncoupling. Arsenate acts as an uncoupler, but only in the presence of adenosine diphosphate (ADP) and magnesium ammonium ions are very effective uncouplers. It is suggested that a ratio of phosphate esterified to electron pairs transferred may be greater than one in the adenosine triphosphate (ATP) formation coupled to ferricyanide reduction.