5'-phosphoribosylformylglycinamide (FGAR) + L-glutamine + ATP + H2O => 5'-phosphoribosylformylglycinamidine (FGAM) + L-glutamate + ADP + orthophosphate

Cytosolic PFAS (phosphoribosylformylglycinamidine synthase) catalyzes the reaction of 5'-phosphoribosylformylglycinamide (FGAR), L-glutamine, ATP, and water to form 5'-phosphoribosylformylglycinamidine (FGAM), L-glutamate, ADP, and orthophosphate. The enzyme has been purified to homogeneity from chicken liver and characterized biochemically, but its amino acid sequence remains unknown so it cannot be associated with a specific chicken gene. The enzyme is active as a monomer, though catalytically active multimers have been observed (Mizobuchi and Buchanan 1968; Frere et al. 1971).

细胞质中的磷酰核糖焦磷酸甲酰甘氨酰胺合成酶催化5'-磷酰核糖焦磷酸甲酰甘氨酰胺（FGAR）、L-谷氨酰胺、ATP和水的反应，生成5'-磷酰核糖焦磷酸甲酰甘氨酰胺（FGAM）、L-谷氨酸、ADP和正磷酸。该酶已从鸡肝中纯化至均一性，并进行了生物化学特性分析，但其氨基酸序列尚不明确，因此无法与特定的鸡基因相联系。该酶以单体形式具有活性，尽管已观察到具有催化活性的多聚体（Mizobuchi和Buchanan 1968；Frere等1971）。