Abstract:

Electrophoresis-purity glutamate dehydrogenase (GDH) from bovine liver was obtained after homogenization,
buffer solution extraction, n-butanol degreasing, ammonium sulfate fractional precipitation, DEAE-Sepharose ion exchange
chromatography and Superdex-200 gel filtration. After purification, the specific activity of GDH was 306.06 U/mg, with
93.60-fold purification; meanwhile, the recovery rate was 23.12%. The molecular weight of GDH was approximately
380.2 kD, in which the subunit molecular weight was roughly 61.7 kD. The results of enzymatic characterization illustrated
that the optimal reaction temperature for GDH was 50 ℃, and it was relatively stable at a temperature below 30 ℃. The
optimal reaction was pH 8.2, and its Km was 0.696 mmol/L towards NADH. The enzyme activity of GDH was inhibited
by methanol, ethanol, isopropanol and metal ions such as Cd2+, Co2+, Ca2+, Ag+, Pb2+, Zn2+, and Cu2+, but enhanced to some
extent by low concentrations of Ba2+, Mg2+, K+, Li+ and EDTA.

Key words: bovine liver, glutamate dehydrogenase, isolation and purification, enzymatic properties