Nitrate reductase inactivation and reducing power and energy charge in chlorella cells

Ammonia, methylamine and other uncouplers of photosynthetic phosphorylation promote in vivo the reversible conversion of the oxidized active form of Chlorella fusca nitrate reductase into its reduced inactive form. Concomitantly with the in vivo inactivation of the enzyme by the uncoupler, there occurs an increase in the cellular levels of the reduced forms of nicotinamide nucleotides and of the uncharged forms of adenine nucleotides. A general view of the regulation of photosynthesis by reducing power and energy charge is discyssed.