title: Stereospecificity of hydrogen transfer by the NADP-linked alcohol dehydrogenase from the thermophilic bacterium Thermoanaerobium brockii.
abstract: Class A and class B NAD(H)/NADP(H) coenzyme-dependent dehydrogenases distinguish between the diastereotopic hydrogens pro-R and pro-S at position 4 of the cofactor. We investigated the stereochemistry of hydride transfer in reactions catalyzed by an unusual thermophilic, zinc-containing, NADP-linked enzyme Thermoanaerobium brockii alcohol dehydrogenase (TBAD). Using proton NMR spectroscopy of monodeuterated alcohols and coenzymes we found that TBAD is a class A enzyme that transfers the pro-R hydrogen from the pyridine 4 position of the reduced coenzyme. This stereospecificity is stable over (a) a broad range of temperatures up to 70 degrees C, (b) different concentrations of the coenzyme (catalytic or stoichiometric) and (c) a wide scope of substrates. Although NAD+ is not an effective coenzyme for TBAD, NADP+ and its synthetic analogs, 3-acetylpyridine-ADP+ and thio-NADP+, can be used successfully.
authors.affiliation: Department of Organic Chemistry, Weizmann Institute of Science, Rehovol, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Peretz
authors.forename: O
authors.initials: O
authors.lastname: Bogin
authors.forename: E
authors.initials: E
authors.lastname: Keinan
authors.forename: Y
authors.initials: Y
authors.lastname: Burstein
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000201:enzymology*; D006859:Hydrogen / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D006859:Hydrogen; D000429:Alcohol Oxidoreductases; C019642:alcohol dehydrogenase (NADP+)