Orientation of Electron Transport Activities in the Membrane of Intact Glyoxysomes Isolated from Castor Bean Endosperm 1

AUTOR(ES)

Luster, Douglas G.

RESUMO

Intact glyoxysomes were isolated from castor bean endosperm on isometric Percoll gradients. The matrix enzyme, malate dehydrogenase, was 80% latent in the intact glyoxysomes. NADH:ferricyanide and NADH:cytochrome c reductase activities were measured in intact and deliberately broken organelles. The latencies of these redox activities were found to be about half the malate dehydrogenase latency. Incubation of intact organelles with trypsin eliminated NADH:cytochrome c reductase activity, but did not affect NADH:ferricyanide reductase activity. NADH oxidase and transhydrogenase activities were negligible in isolated glyoxysomes. Mersalyl and Cibacron blue 3GA were potent inhibitors of NADH:cytochrome c reductase. Quinacrine, Ca2+ and Mg2+ stimulated NADH:cytochrome c reductase activity in intact glyoxysomes. The data suggest that some electron donor sites are on the matrix side and some electron acceptor sites are on the cytosolic side of the membrane.

Documentos Relacionados

• Occurrence of RNA in Glyoxysomes From Castor Bean Endosperm 1
• Cytochemical Localization of Catalase Activity in Glyoxysomes from Castor Bean Endosperm 1
• Temperature-induced Phase Changes in the Membranes of Glyoxysomes, Mitochondria, and Proplastids from Germinating Castor Bean Endosperm 1
• Analysis of Glycoconjugate Saccharides in Organelles Isolated from Castor Bean Endosperm 1
• Lipase Activities in Castor Bean Endosperm during Germination 1