Purification and chemical characterization of alanine dehydrogenase of Bacillus subtilis

1. Bacillus subtilis alanine dehydrogenase (L-alanine: NAD oxidoreductase (deaminating), EC1.4.1.1. has been purified by column chromatography using calcium phosphate gel, DEAE-Sephadex and Ecteola-cellulose; it has been obtained in crystalline form. 2. The sedimentation pattern indicated a homogenous preparation. The sedimentation constant at infinite dilution was 8.8 S. The molecular weight estimated by the sedimentation equilibrium method was 228 000. 3. Amino acid analysis gave the following ratios of amino acid residues: Asp, 43; Thr, 34; Ser, 20; Glu, 51; Pro, 25; Gly, 51; Ala, 65; CySH, 2; Val, 49; Met, 11; iLeu, 28; Leu, 42; Tyr, 15; Phe, 7; Try, 1; Lys, 28; His, 9; Arg, 14.