Phosphoribosyl pyrophosphate synthetase and glutathione reductase in erythrocytes from hyperuricaemic and gout patients

Phosphoribosylpyrophosphate synthetase in human erythrocytes: assay and kinetic studies using high-performance liquid chromatography

A method using high-performance liquid chromatography (HPLC) for determination of phosphoribosylpyrophosphate (PRPP) synthetase activity in human erythrocytes has been developed and PRPP synthetase activity on purine and pyrimidine metabolic disorders has been studied. Kinetic properties of erythrocyte PRPP synthetase of patients with gout and of a patient with pyrimidine 5'-nucleotidase deficiency were compared with those of healthy subjects. The mean of PRPP synthetase activity of gouty patients was a little higher (P less than 0.01) than that of healthy subjects. The response of the enzyme for ATP of gouty patients was different from that of healthy subjects. The shapes of activation curve of the enzyme for inorganic phosphate were hyperbolic in gouty patients and in a patient with pyrimidine 5'-nucleotidase deficiency.

Effect of treatment on erythrocyte phosphoribosyl pyrophosphate synthetase and glutathione reductase activity in patients with primary gout

The activities of erythrocyte phosphoribosyl pyrophosphate (PRPP) synthetase and glutathione reductase (GTR) were studied in 26 patients with primary gout who were receiving no treatment or treatment with either allopurinol or azapropazone, and compared with the activity in a group of healthy controls. The activity of PRPP synthetase was significantly higher in the gout group and was not influenced by either drug. No significant difference in the activity of GTR was observed. The failure of either drug to suppress the increased activity of PRPP synthetase associated with gout is discussed.

A spectrophotometric assay of phosphoribosyl pyrophosphate synthetase

A simple spectrophotometric assay of phosphoribosyl pyrophosphate synthetase from human erythrocytes is described. The kinetic properties of the enzyme have been determined and are in good agreement with published results. Conditions for storing haemolysates at -20 degrees C are described. The method is suitable for semi-automation.