| Literature DB >> 8484798 |
V I Tishkov1, A G Galkin, G N Marchenko, O A Egorova, D V Sheluho, L B Kulakova, L A Dementieva, A M Egorov.
Abstract
Two mutants of bacterial formate dehydrogenase from Pseudomonas sp.101 (EC 1.2.1.2, FDH)-C255S (FDH-S) and C255M (FDH-M), were obtained and its properties were studied. Both mutations provided the high resistance to inactivation by Hg2+. Slow inactivation of mutants by DTNB reveals the presence in FDH molecule of another essential cysteine residue. Specific activities of FDH, FDH-S and FDH-M were 16, 16 and 9.5 U/mg of protein, respectively. Km on formate was 7.5, 7.5 and 20 mM and Km on NAD(+)-0.1, 0.3 and 0.6 mM for FDH, FDH-S and FDH-M, respectively. Mutations of Cys255 on Ser or Met resulted in increasing of enzyme stability at 25 degrees C and decreasing of thermostability (above 45 degrees C). Data obtained show that Cys255 is unique residue for providing both enzyme thermostability and catalytically optimal binding of coenzyme.Entities:
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Year: 1993 PMID： 8484798 DOI： 10.1006/bbrc.1993.1511
Source DB: PubMed Journal: Biochem Biophys Res Commun ISSN： 0006-291X Impact factor: 3.575