this implies that hypoxanthine is the obligatory base for nucleotide synthesis and that the adenine phosphoribosyltransferase ( amp : pyrophosphate phosphoribosyltransferase , ec 2.4.2.7 ) is , in some manner , idenied access to exogenous substrate .
C0597108
nucleotide synthesis
C0001414
adenine phosphoribosyltransferase