. "INHIBITION"^^ . . . . . "'Formation of phosphoribosyl pyrophosphate amidotransferase tetramer' negatively regulates '5-phospho-alpha-D-ribose 1-diphosphate (PRPP) + H2O + L-glutamine <=> 5-phosphoribosylamine + L-glutamate +pyrophosphate'"^^ . .