Abstract
1. An ultracentrifugally homogeneous preparation of the denitrifying enzyme was obtained from cells of a strain of denitrifying bacterium, by the ammonium sulfate fractionation and column chromatography on Amberlite CG-50 and carboxymethyl cellulose.
2. The purified enzyme showed absorption maxima at 280 mμ with a shoulder at about 290 mμ, 594 mμ, and plateaux at about 750-780 mμ and 460-480 mμ, in the oxidized state, while no absorption was observed in the visible region for the reduced enzyme.
3. The determination of sedimentation coefficient (s20, w=6.46 S) and diffusion coeffi-cient (D20, w=4.00×10-7cm2./sec.) lead to a calculated molecular weight of 149, 000.
4. It seems likely that copper is the metal constituent of the denitrifying enzyme.
