Partial purification and properties of NADH dehydrogenase from Propionibacterium shermanii

✍ Scribed by Dr. A. C. Schwartz; A. E. Krause

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 780 KB
• Volume: 15
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.19750150206

✦ Synopsis

Abstract

NADH dehydrogenase (E.C. 1.6.99.3) was purified thirtyfold from the soluble proteins of the anaerobic Propionibacterium shermanii. The identity of the soluble enzyme with the NADH dehydrogenase bound to the particle fraction obtained from ultracentrifugation at 105000 · g for 3 hrs was ascertained by acrylamide gel electrophoresis, hydrogen acceptor specificity, and the close similarity of MICHAELIS constants and maximum velocity. Comparison of the properties of the soluble enzyme to NADH de hydrogenases described in the literature suggests that the isolated enzyme is the initial NADH‐oxidizing flavoprotein from the electron transport system of P. shermanii. The soluble enzyme has a molecular weight of about 215000, and preferentially reduces ferricyanide. MICHAELIS constants were 8.7 · 10^−5^ M for NADH, and 9.4 · 10^−4^ M for ferricyanide. The enzyme is inhibited by both substrates and competitively by NAD. K~i~ for NAD is 1.8 · 10^−4^ M. The absorption spectrum displays a maximum at 408 nm, indicative of the presence of non‐heme iron and labile sulfide.