Role of the Ferredoxin/Thioredoxin System in the Regulation of Photosynthetic Enzymes in a Cyanobacterium

Components of the ferredoxin/thioredoxin system have been identified in cyanobacteria (Schmidt, 1980; Yee et al., 1981). The system was similar to that from higher plants in that it activated thioredoxin-linked enzymes from chloroplasts--i. e., fructose-1,6-bisphosphatase (FBPase) and NADP-malate dehydrogenase (NADP-MDH) However, the two Nostoc thioredoxins, f and m, seemed to be less enzyme-specific than their chloroplast counterparts. In addition, the target enzymes of cyanobacteria were not identified.