Heart mitochondrial creatine kinase revisited: the outer mitochondrial membrane is not important for coupling of phosphocreatine production to oxidative phosphorylation.

摘要: Abstract The state of mitochondrial creatine kinase (CKmi-mi) in intact dog heart mitochondria and mitoplasts the mechanism its functional coupling with oxidative phosphorylation system have been reinvestigated under different osmotic conditions ionic compositions medium. It has established that a medium which mimics cardiac cell cytoplasm, dissociation CKmi-mi from membrane increases when are swollen due to hypoosmotic treatment. was shown by EPR treatment results enhancement mobility phospholipids bilayer. also is detached inner isotonic KCl solution, effects between via ATP ADP translocase disappear spite presence intermembrane space intactness outer membrane. Therefore, this cannot be explained “compartmented coupling” or “dynamic adenine nucleotide compartmentation” diffusion limitation for nucleotides through membrane, as supposed several authors ( F. N. Gellerich et al. (1987) Biochim. Biophys. Acta 890 , 117–126 ; S. P. J. Brooks C. H. Suelter Arch. Biochem. 253 122–132 ). data obtained show displacement enzyme significantly increased sensitivity coupled processes aerobic phosphocreatine synthesis inhibition product, phosphocreatine. Thus, all physiological remains firmly attached effectively intimate dynamic interaction those proteins.