NADP-dependent glutamate dehydrogenase from a facultative methylotroph, Pseudomonas sp. strain AM1. 1984

E Bellion, and F Tan

The NADP-dependent glutamate dehydrogenase (EC 1.4.1.4.) elaborated by the methylotrophic bacterium Pseudomonas sp. strain AM1 when growing on succinate and ammonium chloride was studied. The enzyme, which has a pH optimum of 9.0, was purified 140-fold and shown to have Km values of 20.2 mM, 0.76 mM, 0.033 mM, and 31.6 mM for ammonia, alpha-ketoglutarate, NADPH, and glutamate, respectively. The native molecular weight was determined by polyacrylamide gel electrophoresis to be 190,000, and electrophoresis under denaturing conditions in the presence of sodium dodecyl sulfate revealed a minimum molecular weight of 50,000. The enzyme was highly specific; NADH was unable to replace NADPH in the reaction, various alpha-keto acids could not replace alpha-ketoglutarate, and neither methylamine nor hydroxylamine could substitute for ammonia. Glutamate dehydrogenase was synthesized by the bacteria only when ammonia was its nitrogen source and was repressed if methylamine or nitrate were provided as sources of nitrogen instead of ammonia.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008744 Methylamines Derivatives of methylamine (the structural formula CH3NH2).
D008970 Molecular Weight The sum of the weight of all the atoms in a molecule. Molecular Weights,Weight, Molecular,Weights, Molecular
D009249 NADP Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed) Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D011549 Pseudomonas A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants. Chryseomonas,Pseudomona,Flavimonas
D005969 Glutamate Dehydrogenase An enzyme that catalyzes the conversion of L-glutamate and water to 2-oxoglutarate and NH3 in the presence of NAD+. (From Enzyme Nomenclature, 1992) EC 1.4.1.2. Dehydrogenase, Glutamate
D000643 Ammonium Chloride An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating. Sal Ammoniac,Ammoniac, Sal,Chloride, Ammonium
D013379 Substrate Specificity A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts. Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D013386 Succinates Derivatives of SUCCINIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a 1,4-carboxy terminated aliphatic structure. Succinic Acids,Acids, Succinic
D019802 Succinic Acid A water-soluble, colorless crystal with an acid taste that is used as a chemical intermediate, in medicine, the manufacture of lacquers, and to make perfume esters. It is also used in foods as a sequestrant, buffer, and a neutralizing agent. (Hawley's Condensed Chemical Dictionary, 12th ed, p1099; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1851) Potassium Succinate,Succinate,1,2-Ethanedicarboxylic Acid,1,4-Butanedioic Acid,Ammonium Succinate,Butanedioic Acid,1,2 Ethanedicarboxylic Acid,1,4 Butanedioic Acid,Succinate, Ammonium,Succinate, Potassium

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