ROLE OF CYTOCHROMES AND OTHER METALLOPROTEINS IN THE PHOTOSYNTHETIC ELECTRON TRANSPORT

Publisher Summary This chapter discusses role of cytochromes and other metalloproteins in the photosynthetic electron transport. Current understanding of the mechanism of photosynthesis leans heavily on a concept of a photosynthetic, i.e., light-induced, electron transport. Photosynthetic phosphorylation (photophosphorylation) in chloroplasts is subdivided into two types, cyclic and noncyclic. The cyclic and noncyclic photophosphorylation jointly account for the basic feature of photosynthesis, i.e., conversion of radiant energy into chemical energy. The wavelength dependence of the phosphorylation associated with electron flow from an artificial electron donor (DPIPH2) to NADP resembles the cyclic system. It is well established that treating chloroplasts with ferricyanide in the dark chemically oxidizes several chloroplast constituents including cytochromes. The spectrum of the photoinduced decrease in absorbance had a maximum at 550 nm that was suggestive of an α-peak of a new cytochrome of a c-type.