Open AccessPurification and Properties of NAD-dependent Glutamate Dehydrogenase from Phycomyces Spores
Author(s) -
André J. Van Laere
Publication year - 1988
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-134-6-1597
Subject(s) - glutamate dehydrogenase , nad+ kinase , phycomyces , deamination , nucleotide , biochemistry , enzyme , reductive amination , dehydrogenase , spore , chemistry , oxidative deamination , nucleoside , biology , chromatography , glutamate receptor , catalysis , microbiology and biotechnology , receptor , gene
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.