A highly purified preparation of arginine kinase from the tail muscle of the crayfish, Panulirus longipes, has been used to investigate the mechanism of the reaction. The results of initial velocity, product inhibition, and isotope exchange at equilibrium studies are consistent with the reaction having a random mechanism in which all the steps are in rapid equilibrium except those concerned wit...

Initial-rate studies were made of the oxidation of L-glutamate by NAD+ and NADP+ catalysed by highly purified preparations of dogfish liver glutamate dehydrogenase. With NAD+ as coenzyme the kinetics show the same features of coenzyme activation as seen with the bovine liver enzyme [Engel & Dalziel (1969) Biochem. J. 115, 621--631]. With NADP+ as coenzyme, initial rates are much slower than wit...

With the discovery that pyridoxal phosphate and pyridoxamine phosphate were cofactors for enzymatic transamination, it was proposed that the reaction was biphasic, involving first an amino group transfer from the amino acid substrate to enzymebound pyridoxal phosphate, followed by a transfer of the amino group to the keto acid substrate (for review, see (1)). With the availability of a highly p...