Hypoxanthine-guanine phosphoribosyl transferase: assay using high performance liquid chromatography

A method is described for the estimation of hypoxanthine-guanine phosphoribosyltransferase using high performance liquid chromatography. The inosine monophosphate (IMP) generated from hypoxanthine is determined, after separation on a C18 reversed phase silica column with a buffer-methanol gradient, by the absorbance at 254 nm. Simultaneous reciprocal measurement of hypoxanthine consumption is made. The assay is suitable for screening red cell lysates for hypoxanthine-guanine phosphoribosyltransferase deficiency; the results being expressed as nmol inosine monophosphate . h-1. mg-1 haemoglobin. The normal range found was 94 +/- 15 nmol IMP . h-1 . mg-1 haemoglobin and hypoxanthine-guanine phosphoribosyltransferase activities down to 1% of normal can be assayed accurately.