Compartmentation and metabolic parameters of mitochondrial hexokinase and creatine kinase depend on the rate of oxidative phosphorylation.

Oxidative phosphorylation in rat heart mitochondria was stimulated by the presence of hexokinase, by simultaneous operation of mitochondrial hexokinase and creatine kinase, or by mitochondrial hexokinase plus exogenously added phosphofructokinase. Under these conditions, 32Pi studies were conducted to estimate the extent of ATP compartmentation in the mitochondria in the vicinity of the active sites of hexokinase and creatine kinase. In all cases studied the extent of ATP compartmentation at 500 microM ATP concentration was no more than 12%.

Kinetic properties of the octameric and dimeric forms of mitochondrial creatine kinase and physiological role of the enzyme.

It has been found that at pH 7.4 and 2 mg/ml protein, bovine heart mitochondrial creatine kinase (CKm) contains less than 10% of the dimer. The constant for the CKm octamer dissociation into dimers, Kd, in the presence of substrates forming an analog of the complex of the transient state was found to be equal to 4.

The quaternary structure of bovine heart mitochondrial creatine kinase.

Crosslinking of subunits of the high molecular weight oligomer of bovine heart mitochondrial creatine kinase (CKm) by dimethyl suberimidate and subsequent electrophoresis in the presence of sodium dodecyl sulfate gives eight protein bands. An increase in the time course of the enzyme crosslinking reaction results in the protein accumulation in the high molecular weight bands. Evidence has been obtained suggesting that crosslinking involves only the intraoligomeric contact areas.

Study on heart mitochondrial creatine kinase using a cross-linking bifunctional reagent. II. The binding sites for the creatine kinase octamer on mitochondrial membranes have different properties.

Beef heart mitochondria suspended in 0.25 M sucrose were treated with 0.3% glutaraldehyde (GA).

Study on heart mitochondrial creatine kinase using a cross-linking bifunctional reagent. I. The binding involves the octameric form of the enzyme.

Bovine heart mitochondria suspended in 0.25 M sucrose were treated with 0.3% glutaraldehyde (GA).

Studies of the interaction of mitochondrial creatine kinase with the mitochondrial membrane.

In this study we have investigated the binding characteristics of creatine kinase (CK) with mitochondrial membrane. Creatine kinase was found to bind membranes by electrostatic forces. At physiological pH, the interaction seems to be between positively charged groups on the enzyme protein and negatively charged groups on the membrane.