Hypoxanthine-guanine phosphoribosyltransferase: A simple spectrophotometric assay

A simple spectrophotometric assay is described based on the conversion of hypoxanthine to inosine monophosphate and precipitation of both the reaction product and protein with lanthanum phosphate. The extent of conversion is determined by the fall in absorbance of hypoxanthine at 249 nm. The assay is suitable for screening red cell lysates for hypoxanthine-guanine phosphoribosyl-transferase deficiency