[Interactions between heart mitochondrial creatine kinase and oxidative phosphorylation]. / Vzaimodistvie mezhdu kreatinkinazoi mitokhondrii serdtsa i okislitel'nym fosforilirovaniem.

The conditions for chromatographic separation in Silufol plates of adenine nucleotides, creatinine phosphate, glucose-6-phosphate and Pi have been found. Using this method, it was shown that in the presence of Pi and non-labelled ATP the specific radioactivity of creatine phosphate formed by mitochondrial creatinine kinase via oxidative phosphorylation increases at the same rate as does the specific radioactivity of the surrounding solution of ATP. It is concluded that under the given experimental conditions the ATP formed via oxidative phosphorylation enters the enzyme active center only after it has passed into the solution rather than immediately from the adenine nucleotide carrier.

[Interaction between mitochondrial creatine kinase and mitochondrial membranes]. / Issledovanie vzaimodeistviia mitokhondrial'noi kreatinkinazy s membranami mitokhondrii.

The outer mitochondrial membrane of beef heart was disrupted by hypotonic treatment and the effects of concentration and ionic strength of creatine kinase substrate solutions and some other electrolytes and non-electrolytes on mitochondrial membrane creatine kinase were studied. It was shown that electrostatic forces play an important role in the binding of creatine kinase to the mitochondrial membrane. It was assumed that under physiological conditions mitochondrial creatine kinase may undergo a reversible association - dissociation reaction with the membrane. The changes of pH within the range of 6.0 to 9.5 had no effect on the creatine kinase binding to mitochondrial membrane. Creatine kinase from beef heart mitochondria binds likewise and at the same rate to the rat liver no creatine kinase. The number of binding sites in mg of heart mitochondrial protein is n1 = 0.54 +/- 0.11 nmole, Kd1 = 0.16 +/- 0.04 microM. The number of binding sites in mg of liver mitochondrial protein is n2 = 0.65 +/- +/- 0.03 nmole, Kd2 = 0.29 +/- 0.09 microM. Excessive cytochrome c inhibits the binding of creatine kinase to the beef heart mitochondrial membrane. The results obtained suggest that mitochondrial creatine kinase is apparently bound to the membrane phospholipids.