Purification and kinetic characteristics of dogfish liver glutamate dehydrogenase.

A method for the purification of glutamate dehydrogenase from dogfish liver has been presented. The molecular weight of the enzyme has been determined and the sedimentation constant has been found to be invariant over a wide range of concentrations, in contrast to the bovine liver glutamate dehydrogenase. Upon electrophoresis the dogfish enzyme has been observed to migrate further than the beef or chicken enzymes under all conditions studied. The kinetic parameters of the enzymatic reaction with the triphosphopyridine nucleotides have been explored; they indicate a sequential order of substrate addition analogous to that found for other glutamate dehydrogenases. The maximum velocities obtained by extrapolation of reciprocal plots of specific activities against low concentrations of reduced dinhosphopyridine nucleotide have been found to be virtually identical for bovine, chicken, and dogfish liver glutamate dehydrogenases.