Characterization of meso-Diaminopimelate Dehydrogenase from Corynebacterium glutamicum and Its Distribution in Bacteria

meso-Diaminopimelate dehydrogenase (EC 1.4.1.16) was purified to homogeneity from Corynebacterium glutamicum ATCC 13032. The enzyme had a molecular weight of about 70,000 and consisted of two subunits identical in molecular weight. The enzyme was highly specific for meso-2,6-diaminopimelate. The pH optima for deamination and amination were about 9.8 and 7.9, respectively. The Michaelis constants were 3.1mm for meso-2,6-diaminopimelate, 0.12mm for NADP+, 0.28 mm for l-2-amino-6-ketopimelate, 36 mm for ammonia, and 0.13 mm for NADPH. d and l isomers of 2,6-diaminopimelate competitively inhibited the oxidative deamination of meso-2,6-diaminopimelate. The enzyme was distributed in a wider range of bacterial species than reported previously [Misono et al., J. Bacteriol., 137, 22 (1979)] when assayed by a sensitive formazan formation method.