Biochemical characterization of Formate Dehydrogenase from Desulfovibrio desulfuricans.

M.G. RIVAS; C.S. MOTA; P.J. GONZÁLEZ; C.D. BRONDINO; J.J.G. MOURA; I. MOURA

Tomar (Portugal)

Congreso; Meeting on Microbial Respiratory Chains.; 2006

Formate dehydrogenase (Fdh) catalyzes the oxidation of formate to carbon dioxide. Fdh from Desulfovibrio desulfuricans has a molecular mass of approximately 150 kDa and is composed by 3 subunits (88, 29 and 16 kDa) and contains Mo-pterin, [4Fe-4S] and c-type hemic redox active centers. We report kinetics studies using formate and deuterioformate as substrate that were carried out to elucidate the importance of the cleavage C-H bond in the reaction mechanism. The behavior towards inhibitors such as azide, cyanide and nitrate is also reported. These studies show a mixed inhibition pattern for azide and cyanide, with kinetic parameters similar to those reported for other Fdhs. Nitrate showed a competitive inhibitor pattern with respect to formate.