Interaction of Photosynthetic and Respiratory Electron Transport in Blue-Green Algae: Effect of a Cytochrome c-553 Specific Antibody

Abstract

An antibody prepared against purified cytochrome c-553 from Nostoc muscorum inhibits the redox function of cytochrome c-553 as checked by a diaphorase assay. 20 to 30% inhibition of NADPH-driven respiratory and light-induced oxygen uptake by Nostoc thylakoids is observed when cytochrome c-553 specific antibodies were applied. However, only 30 to 50% of the total cytochrome c-553 content is released from isolated membrane material, thus being accessible to antibodies. Supplementing the isolated membrane material with excess Nostoc cytochrome before adding the antibody abolishes inhibition. The data provide further evidence for soluble cytochrome c-553 being a link between photosynthetic and respiratory electron transport in blue- green algae.