Phosphoribosylpyrophosphate synthetase (PRS; EC 2.7.6.1), an essential enzyme for the purine salvage
pathway, is encoded by PRPS1 gene. Several mutations in this gene associated with genetic disorders have
been described leading to
PRS superactivity
. This condition is inherited in an X-linked pattern.
PRPS1 gene overactivity increases the production of normal PRPP synthetase 1 enzyme, which increases the
availability of PRPP. Excessive amounts of purines are generated leading to an accumulation of uric acid, a
waste product of purine breakdown, in the body. A buildup of uric acid can cause gout, which is a form of
arthritis resulting from uric acid crystals in the joints. Affected individuals may also develop kidney or
bladder stones formed from uric acid crystals.
Increase of the availability of PRPP can be due to PRPP-S superactivity or HPRT deficiency (know more about
HPRT assay
).
PRECICE® PRPP-S Assay Kit is designed for continuous monitoring of PRPP synthesis. The assay is based on coupling of two recombinant enzymes: Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and Inosine Monophosphate Dehydrogenase (IMPDH).
Specific activitiy of PRS in lysates of human erythrocytes measured by PRECICE® PRPP-S Assay kit is close to previously published data.
| RBC speciment 1 (n=4) | 65+/-2 nmol/hour/mg Hb |
| RBC speciment 2 (n=4) | 76+/-12 nmol/hour/mg Hb |
| RBC speciment 3 (n=4) | 78+/-10 nmol/hour/mg Hb |
| Published data R. B. Gordon et al J. Inher. Metab. Dis. 10 (1987) 82, 88 | 102+/-20nmol/hour/mg Hb |
Simultaneous analysis of up to 6 samples in duplicate in 1h.
PRS activity is measured as a rate of production of PRPP with concomitant formation of NADH2 after two enzymatic reactions using highly active HPRT and IMPDH. The formation of NADH2 is continuously monitored spectrophotometrically at 340nm.