Characterization of meso-diaminopimelate dehydrogenase from Corynebacterium glutamicum and its distribution in bacteria.

maso-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 3.1 mM for maso-2, 6-diaminopimelate, 0.12 mm 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 maso-2, 6-diaminopimelate. The enzyme was distributed in a wider range of bacterial species than reported previously [Misono et al., J. Bacterial., 137, 22 (1979)] when assayed by a sensitive formazan formation method.