Isolation and Partial Characterization of the Membrane-Bound NADH Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata
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چکیده
The membrane-bound NADH dehydrogenase (E.C. 1.6.99.3) has been solubilized by sodium deoxycholate treatment of membranes and purified 75 fold by column chromatography on Sephadex G-150 and DEAE cellulose in the presence of sodium cholate. The native enzyme has an apparent molecular mass (M r) of 97 000, containing polypeptides of Mr of about 15 000. The pH optimum was at 7.5. The enzyme was specific for NADH. The Michaelis constant for NADH and DCIP were 4.0 and 63 hm, respectively. The enzyme was inactivated by FMN, riboflavin and NADH. In contrast, the soluble NADHdehydrogenase (i) was activated by FMN.
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