The binding of glycerol kinase to the outer membrane of rat liver mitochondria: its importance in metabolic regulation.
Glycerol kinase was found to associate with the hexokinase binding protein. The binding of glycerol kinase has a high specificity as illustrated by the fact that the magnitude of binding was reduced by glycerophosphate and antibodies against the hexokinase binding protein. A possible function of glycerol kinase binding to the mitochondria with respect to metabolic regulation is proposed for the following reasons: (i) Glycerol kinase seems to bind to the same binding protein as hexokinase. (ii) Both kinases were observed to be reversibly bound to the mitochondria in different metabolic situations, i.e., 10% of total cellular activity from both kinases is bound in starved rats whereas no activity of glycerol kinase and 30% of hexokinase become bound in fed rats. (iii) The kinetic properties of the associated glycerol kinase change in an analogous manner to those known for structure-bound hexokinase. (iv) With the binding of glycerol kinase to the mitochondria, it is possible to propose a metabolic pathway for glycerol oxidation to dihydroxyacetone phosphate by a combined action involving the enzyme, glycerol phosphate oxidase, and oxidative phosphorylation.
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000378:metabolism; D005215:Fasting; D005991:Glycerol Kinase / Q000378:metabolism*; D006593:Hexokinase / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D010770:Phosphotransferases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002352:Carrier Proteins; D004040:Dietary Carbohydrates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D006593:Hexokinase; D005991:Glycerol Kinase