Enzymic phosphorylation of creatine by 1:3-diphosphoglyceric acid

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Abstract
An enzyme preparation has been obtained from rat skeletal skeletal muscle that transfers the carbonyl phosphate of 1,3-diphosphoglyceric acid to creatine without the addition of adenosine diphosphate. The presence of adenosine diphosphate as a contaminant in the various preparations was excluded by the use of enzyme tests which would detect it. Acetyl phosphate was ineffective. Enzymes utilizing adenosine triphosphate do not inhibit the direct transfer of phosphate from 1,3-diphosphoglyceric acid to creatine, whereas they inhibit creatine phosphokinase. The enzyme system described, and creatine phosphokinase, exhibit differences in their requirements for creatine, their heat stability and the inhibition caused by ammonium sulfate and monoiodoacetate. Heart-muscle preparations contain creatine phosphokinase but not the direct phosphate-transfer system. The possibility of phosphate transfer directly from 1,3-diphosphoglyceric acid to creatine, and the existence of an enzyme different from creatine phosphokinase and from acyl phosphatase, are discussed. The name suggested for the new enzyme is 1,3-diphosphoglycerate-creatine phosphotransferase.