2.4.2.8 hypoxanthine phosphoribosyltransferase; IMP pyrophosphorylase; transphosphoribosidase; hypoxanthine---guanine phosphoribosyltransferase; guanine phosphoribosyltransferase; GPRT; HPRT; guanosine 5'-phosphate pyrophosphorylase; IMP-GMP pyrophosphoryla • • •