Biomaterial Database

[Investigation of essential SH-groups of bacterial formate dehydrogenase]. 1979

V O Popov, and A M Egorov

Modification of two SH-groups in the molecule of formate dehydrogenase by dithiobisnitrobenzoate or to dacetamide results in the enzyme inactivation. Coenzymes, but not the substrate, protect the enzyme against the inactivation. NAD in the presence of potassium azide completely preserves the enzyme activity. Two SH-groups per enzyme molecule are protected from modification. The Km values for partially inactivated formate dehydrogenase remain constant for both substrates. The enzyme with modified SH-groups does not bind conezymes. The pH-dependence of the inactivation rate reveals the ionizable group with pK 9.6 (25 degrees C). The involvement of essential SH-groups in coenzyme binding is discussed.

UI	MeSH Term	Description	Entries
D007460	Iodoacetamide	An alkylating sulfhydryl reagent. Its actions are similar to those of iodoacetate.
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D004228	Dithionitrobenzoic Acid	A standard reagent for the determination of reactive sulfhydryl groups by absorbance measurements. It is used primarily for the determination of sulfhydryl and disulfide groups in proteins. The color produced is due to the formation of a thio anion, 3-carboxyl-4-nitrothiophenolate.	5,5'-Dithiobis(2-nitrobenzoic Acid),DTNB,Ellman's Reagent,5,5'-Dithiobis(nitrobenzoate),Acid, Dithionitrobenzoic,Ellman Reagent,Ellmans Reagent,Reagent, Ellman's
D005561	Formates	Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.	Formic Acids,Acids, Formic
D000445	Aldehyde Oxidoreductases	Oxidoreductases that are specific for ALDEHYDES.	Aldehyde Oxidoreductase,Oxidoreductase, Aldehyde,Oxidoreductases, Aldehyde
D001386	Azides	Organic or inorganic compounds that contain the -N3 group.	Azide
D001419	Bacteria	One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.	Eubacteria
D013438	Sulfhydryl Compounds	Compounds containing the -SH radical.	Mercaptan,Mercapto Compounds,Sulfhydryl Compound,Thiol,Thiols,Mercaptans,Compound, Sulfhydryl,Compounds, Mercapto,Compounds, Sulfhydryl