Selective expression of phosphoribosylpyrophosphate synthetase superactivity in human lymphoblast lines.

Selective expression of phosphoribosylpyrophosphate synthetase superactivity in human lymphoblast lines.

Phenotypic expression of 5-phosphoribosyl 1-pyrophosphate (PRPP) synthetase superactivity was examined in lymphoblast lines derived from six unrelated male patients. Fibroblasts from these individuals have increased rates of PRPP and purine nucleotide synthesis and express four classes of kinetic derangement underlying enzyme superactivity: increased maximal reaction velocity (catalytic defect)...

Phosphoribosylpyrophosphate synthetase superactivity

Variant human phosphoribosylpyrophosphate synthetase altered in regulatory and catalytic functions.

An inherited, structurally abnormal and superactive form of the enzyme 5-phosphoribosyl 1-pyrophosphate (PP-ribose-P) synthetase (EC 2.7.6.1) has been characterized in fibroblasts cultured from a 14-yr-old male (S.M.) with clinical manifestations of uric acid overproduction present since infancy. PP-ribose-P synthetase from the cells of this child showed four- to fivefold greater than normal re...

Human phosphoribosylpyrophosphate synthetase. Kinetic mechanism and end product inhibition.

Human PP-ribose-P synthetase, partially purified from erythrocytes, was found to have Michaelis constants for ribose-S-P, MgATP, and magnesium of 33 PM, 14 PM, and 0.2 mu, respectively. Based on studies of initial velocity and product inhibition, the kinetic mechanism is postulated to be an ordered Bi BE reaction with ribose-5-P binding first and PP-ribose-P being released last. Magnesium binds...

Feedback-Resistant Phosphoribosylpyrophosphate Synthetase Associated with Purine Overproduction and Gout PHOSPHORIBOSYLPYROPHOSPHATE AND PURINE METABOLISM

other family members investigated. The fibroblast studA preliminary report was presented at the Annual Meeting of the Israeli Association of Chemical Pathology, Rehovot, Israel, March 1974. Professor de Vries is an Established Investigator of the Chief Scientist's Bureau, Ministry of Health. Received for publication 6 February 1975 and in revised form 7 July 1975. ies demonstrate the following ...