Photooxidase Activity of Heated Chromatophores of Rhodospirillum rubrum.

Van Niel's classical distinction between bacterial and green plant photosyntheses is based on the differences in the metabolism of the photooxidant (16). But direct measurement of the oxidizing power in bacterial photosynthesis is, at best, difficult with the usual spectrophotometric equipment. Light-induced oxidations of endogenous cytochromes have been demonstrated in whole cells and extracts of Rhodospirillffii rubrurn (2, 4, 15), but special spectrophotometers were always required. The oxidizing power generated by light was easily measured by Vernon and Kamen using as the assay the photooxidation of reduced indophenol or exogenous mammalian cyto-