title: [The role of histidine residues of formate dehydrogenase from Bacterium sp. 1].
abstract: The reaction between formate dehydrogenase from Bacterium sp. 1 and diethylpyrocarbonate results in the enzyme inactivation. 4 histidine residues can be blocked per subunit by this reagent. The enzyme activity correlates with the disappearance of free histidines. The process of enzyme inactivation is biphasic and obeys pseudo-first-order kinetics. NAD and NADH slow down the rate of inactivation, but do not protect histidine residues against modification. Formate does not protect the enzyme. The modification of 80% of histidines increases the Km value for both substrates 3-fold. The general conformation of enzyme in the course of modification is preserved. The modification of histidines markedly decreases the reactivity of an essential SH-group of formate dehydrogenase against the Ellman reagent.
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology; D004047:Diethyl Pyrocarbonate; D004228:Dithionitrobenzoic Acid; D005561:Formates; D006639:Histidine / Q000378:metabolism*; D007700:Kinetics; D009243:NAD / Q000378:metabolism
chemical_list: D005561:Formates; D009243:NAD; D006639:Histidine; D004228:Dithionitrobenzoic Acid; D000445:Aldehyde Oxidoreductases; D004047:Diethyl Pyrocarbonate
vernacular_title: Izuchenie roli ostatkov gistidina formiatdegidrogenazy iz Bacterium sp.1.