Evidence for a dissociative SN1(P) mechanism of phosphoryl transfer by rabbit muscle pyruvate kinase
Abstract
Pyruvate kinase from rabbit muscle catalyses the randomisation of 18O between Pβ–18O2 and Pγ–O–Pβ in adenosine 5′[αβ-18O,β18O2]-triphosphate in the presence of pyruvate and oxalate and in their absence, the first order rate constants being 2·0 × 103, 2·0 × 102, and 1·1 × 102 min–1, respectively, which indicates that phosphoryl transfer occurs by a dissociative SN1(P) mechanism.