The interaction between phosphoryl transferase and submitochondrial particles

Abstract

The interaction between purified phosphoryl transferase and submitochondrial particles has been studied. In the presence of submitochondrial particles the transferase is phosphorylated and the phosphorylated form of the transferase is dephosphorylated. Both of these interactions require that the particle be actively carrying out oxidation of succinate or NADH. Both antimycin A and oligomycin suppress the phosphorylation and dephosphorylation reactions. The uncoupler p-trifluoromethoxy-carbonylcyanide phenylhydrazone prevents the particle-mediated phosphorylation of the transferase but stimulates the dephosphorylation of the phosphorylated transferase to a slight extent. The concentration of bound adenine nucleotide in the particles appears to be a major determinant of the rate of phosphorylation of the transferase, and this dependence is consistent with the fact that the transfer of a phosphoryl group from the phosphorylated transferase to ADP proceeds rapidly and spontaneously. The probable role of the transferase in the mitochondrial transfer of phosphoryl groups from endogenous ATP to exogenous ADP is evaluated.