Purification and properties of NAD-dependent glutamate dehydrogenase from Phycomyces spores.
The NAD-dependent glutamate dehydrogenase from Phycomyces spores was purified more than 300-fold. Estimation of Mr by gel filtration gave a value of 98,000 whereas after SDS-PAGE one major band of Mr 54,000 was found, suggesting that the enzyme is a dimer. The enzyme was virtually dependent on the presence of AMP for activity and showed half-maximal activation at 9.5 and 43 microM-AMP in the direction of animation and deamination respectively. ADP was nearly as effective at 20-fold higher concentrations. Other nucleotide monophosphates were ineffective and nucleoside triphosphates were slightly inhibitory. Hyperbolic kinetics were found for all substrates yielding Km values of about 10 mM for ammonium, 1 mM for 2-oxoglutarate and 0.1 mM for NADH in the direction of amination, and 10 mM for glutamate and 0.7 mM for NAD in the direction of deamination.
Van Laere
A J
AJ
Department of Plant Physiology and Biochemistry, Katholieke Universiteit Leuven, Heverlee, Belgium.
D005969:Glutamate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009090:Mucorales / Q000201:enzymology*; D009243:NAD / Q000378:metabolism*; D010800:Phycomyces / Q000201:enzymology*; D013172:Spores, Fungal / Q000201:enzymology
D009243:NAD; D005969:Glutamate Dehydrogenase