Functions of Enolphosphates and Epoxycarotenoids in Photophosphorylation

As was shown in our previous work, the rate of photophosphorylation does not depend on the concentration of inorganic phosphate but only on the rate of interconversion of intermediates (BERSHTEIN et al. 1969). Many phosphorous ethers, tested in our experiments, did not affect the rate of photphosphory1 at ion (BERSHTEIN et al. 1970). We found out, still, that acetophosphate (AP) and PEP, added to the photophosphorylating system in equimolar to ADP concentrations, inhibited inorganic phosphate incorporation into photophosphorylation. In this case the phosphoether groups of these compounds serve as a donor of phosphate for ATP formation. Unlike, PEP, AP in comparatively low concentrations stimulated inorganic phosphate incorporation. Pyridoxal phosphate (PP), introduced simultaneously, could enhance this stimulating effect (Fig. 1).