Properties of glutamate dehydrogenase from Beta vulgaris

Abstract

Glutamate‐NAD oxidoreductase, E.C. 1.4.1.3 (GDH), from seedlings of Beta vulgaris cv. Rota, Jahnsch Peragis Comp., was enzymatically characterized. This enzyme with molecular weight of 2.6 × 105 has a pH optimum of around 8 for animation of α‐KGA and around 9.5 for the desamination of glutamate. The apparent Km for α‐KGA is 6.7 × 10−4M, for NH3 2.5 × 10−3M, for NADH 3.2 × 10−5M and for NAADPH 5.5 × 10−4M. NAD1 inhibits the reaction non‐competitively when NADPH serves as substrate. The apparent K1 is 4.5 × 10−4M. The data are discussed on relation to the properties of GDH from other plant sources.

Characterization of glutamine‐synthetase from Beta vulgaris

“…Rota, Jansch Peragis Company). The plants were grown in hydroculture as described (Nesselhut and Harnischfeger 1980). The seedlings (100-150 g) were homogenized with 200-300 ml 15 mM MgSO4-8 mM mercaptoethanol -10 mM ATP -0.1 M imidazole-buffer pH 7.9.…”