2.4.2.17 1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate = ATP + 5-phospho-alpha-D-ribose 1-diphosphate double displacement mechanism 637662 2.4.2.17 1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate = ATP + 5-phospho-alpha-D-ribose 1-diphosphate sequential kinetic mechanism in biosynthetic direction, ordered bi-bi mechanism with ATP binding first to free enzyme and phosphoribosyl-ATP dissociating last from enzyme-product complexes 637662, 637663, 637670, 637671 2.4.2.17 1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate = ATP + 5-phospho-alpha-D-ribose 1-diphosphate substrate binding sites, active site structure, switch between active and inactive conformation 659495 2.4.2.17 1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate = ATP + 5-phospho-alpha-D-ribose 1-diphosphate substrate binding sites, e.g. Cys104, Asn75, Ser154, Glu156, and Val155, reaction mechanism 659707