PLANT PHYSIOLOGY · 1981 · 29 citations · 17 references
Life SciencesBiochemistryBotanyEnzymologyPhotosynthesisPlant BiochemistryChloroplast BiochemistryChloroplast BioenergeticsElectron Transport ChainPhotosynthesis BiochemistryPhotosynthetic Energy ConversionPhotosystem IAdenosine Triphosphate SynthesisAtp Synthesis InhibitionCyclic PhotophosphorylationEnergy TransferEnergy Transfer MechanismsPhotosynthetic ControlPhotosynthetic Electron TransferPhotosynthetic Electron Transport
Two hydroxamic acids isolated from maize extracts, 2,4-dihydroxy-7-methoxy-1,4-(2H)-benzoxazin-3(4H)-one (DIMBOA) and the 2-O-beta-d-glucopyranoside of DIMBOA, inhibit photophosphorylation by spinach chloroplasts. Both cyclic and noncyclic photophosphorylations were inhibited to the same extent. The concentrations producing 50% inhibition for DIMBOA and its glucoside were about 1 and 4 millimolar, respectively. These compounds inhibit coupled electron transport but do not affect basal or uncoupled electron transport. Both acids inhibit the ATPase activities of membrane-bound coupling factor 1 (CF(1)) and of purified CF(1). On the basis of these results, it is concluded that DIMBOA and its glucoside act as energy transfer inhibitors of photophosphorylation.
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