Biomaterial Database

Kinetics of the diacetyl and 2,3-pentanedione reduction by diacetyl reductase (alpha-diketone reductase (NAD)) from Staphylococcus aureus. 1988

J González, and I Vidal, and A Bernardo, and R Martin

Facultad de Veterinaria, Universidad de León, Spain.

The kinetic mechanism of diacetyl and 2,3-pentanedione reduction by diacetyl reductase from Staphylococcus aureus was investigated. The shape of the primary double reciprocal plots, the product inhibition pattern, and the features of the inhibition by a substrate analogue (acetone) show that diacetyl is reduced via an Ordered Bi-Bi mechanism, and 2,3-pentanedione by an Ordered Bi-Bi or Theorell-Chance mechanism. NADH is the leading substrate in both reactions. Affinity constants for the coenzyme and the substrates and inhibition constants for NAD, acetoin, and acetone were also calculated. This enzyme has a high affinity for NADH; Km (31-50 microM) and Ks (20-27 microM) for this compound are around one-tenth of the NADH intracellular concentration. Therefore, it must operate in vivo saturated with the coenzyme. This condition is not adequate to play the role, formerly proposed for diacetyl reductases, of regulating the equilibrium between oxidized and reduced forms of pyridine-nucleotides.

UI	MeSH Term	Description	Entries
D007659	Ketones	Organic compounds containing a carbonyl group	Ketone
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010422	Pentanones	5-carbon straight-chain or branched-chain ketones.	Diethyl Ketones,Methyl Propyl Ketones,Ketones, Diethyl,Ketones, Methyl Propyl,Propyl Ketones, Methyl
D002074	Butanones	Derivatives of butanone, also known as methyl ethyl ketone (with structural formula CH3COC2H5).
D003931	Diacetyl	Carrier of aroma of butter, vinegar, coffee, and other foods.	2,3-Butanedione,Biacetyl,Diketobutane,Dimethyldiketone,Dimethylglyoxal,2,3 Butanedione
D000094	Acetoin Dehydrogenase	An enzyme that catalyzes the conversion of acetoin to diacetyl in the presence of NAD.	Diacetyl Reductase,Diacetyl Reductase ((R)-Acetoin Forming),Diacetyl Reductase ((S)-Acetoin Forming),Dehydrogenase, Acetoin,Reductase, Diacetyl
D000429	Alcohol Oxidoreductases	A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).	Carbonyl Reductase,Ketone Reductase,Carbonyl Reductases,Ketone Reductases,Oxidoreductases, Alcohol,Reductase, Carbonyl,Reductase, Ketone,Reductases, Carbonyl,Reductases, Ketone
D000494	Allosteric Regulation	The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.	Regulation, Allosteric,Allosteric Regulations,Regulations, Allosteric
D013211	Staphylococcus aureus	Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.