Purification and characterization of NADP+-specific glutamate dehydrogenase fromEscherichia coli
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The NADP+-specific glutamate dehydrogenase fromEscherichia coli has been purified to electrophoretic homogeneity. The enzyme was purified 40-fold and has a specific activity of 23. Glutamate dehydrogenase fromE. coli is a hexameric enzyme with a native molecular weight of 275 KDa composed of monomers each with a molecular weight of 44.5 KDa. In nondenaturing isoelectric focusing gels, the purified enzyme is resolved into six catalytically active species, each with a molecular weight of 275 KDa and with isoelectric points ranging between pH 5.3 and 5.7. The Km values for substrates and coenzymes have been determined, and the effect of several divalent ions on catalytic activity has been investigated.
KeywordsEnzyme Molecular Weight Purification Glutamate Catalytic Activity
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