phosphoribosyl-N-formylglycineamide /ˌfɑːsfəˌraɪbəˈsaɪl ɛn ˌfɔːrməlˌɡlaɪsiːnəˈæmaɪd/ noun1 •A phosphorylated ribonucleotide intermediate in the de novo purine biosynthesis pathway, formed from glycinamide ribonucleotide and converted into phosphoribosylformylglycinamidine.