Phosphoribosylpyrophosphate synthetase superactivity

The synthesis of phosphoribosylpyrophosphate from ATP and ribose-5-phosphate is catalyzed by phosphoribosylpyrophosphate synthetase. Superactivity of this enzyme may be a cause of overproduction of uric acid, which may result in gout. 

PHOSPHORIBOSYLPYROPHOSPHATE SYNTHETASE SUPERACTIVITY DETECTION, CHARACTERIZATION OF UNDERLYING DEFECTS, AND TREATMENT... 

Table 23.8. Phosphoribosylpyrophosphate synthetase superactivity [Patients 24 (world)]...

Phosphoribosylpyrophosphate (PRPP) synthetase (E.C. 2.7.6.1) catalyzes the formation of PRPP from ribose-5-phosphate and ATP in the presence of Mg and inorganic phosphate. The product, PRPP, is a substrate of the first rate limiting step of the de novo synthesis of purine nucleotides and its availability has been shown to regulate this pathway in human tissue (l). A superactive mutant erythrocyte PRPP synthetase with decreased sensitivity to feedback inhibition has recently been found by us in a gouty family (2,3). 

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