[Functional coupling of creatine phosphokinase and adenylate kinase with adenine nucleotide translocase and its role in regulation of heart mitochondrial respiration].

The respiration of rabbit heart mitochondria in the presence of ATP is stimulated by ADP, AMP, creatine and glucose plus hexokinase. The values of V for mitochondrial phosphorylating respiration in the presence of corresponding stimulators are equal to 491 +/- 34, 460 +/- 12, 480 +/- 45 and 463 +/- 72 natoms O2 X min-1 X mg-1 of protein, 37 degrees C. The half-maximal stimulation of respiration is observed at 35 microM AMP, 60 microM ADP and 10 mM creatine in the absence of creatine phosphate. In the presence of creatine phosphate the maximal stimulation of heart mitochondrial respiration is achieved under a combined action of creatine and AMP. The inhibition type of mitochondrial respiration by palmitoyl-CoA depends on the nature of stimulators used. Thus, with ADP or glucose plus hexokinase the inhibition is competitive, while with AMP and creatine an uncompetitive and non-competitive inhibition was observed, respectively. The experimental results are indicative of functional coupling of heart mitochondrial adenylate kinase and creatine phosphokinase with ATP-ADP-translocase. It is assumed that creatine and AMP act as physiological regulators of heart mitochondrial respiration ("feed-back" signals from cytoplasm to mitochondria).