MAT2B and cancer: Human Mat2A is a pharmacologicallyvalidated target for the developmentof novel anti-cancer therapeutics for patients with MTAP-deleted cancers,which account for 15% of all cancers.24,25 There areconflicting reports describing Mat2A following random or ordered kineticmechanisms.12,20,21 In addition, different reports have described Mat2B as an inhibitoror an activator of Mat2A.10,13,31−33 In this work, we present comprehensive steady-statekinetics and binding results that allowed us to determine the steady-statemechanism of human Mat2A and the effect of Mat2B.