ABSTRACT
The stereochemical course of the reduction of acetaldehyde to ethanol was investigated by evaluating, with the enzymic system yeast alcohol dehydrogenase/diaphorase and g.c.-m.s., the configuration of [1-2H]ethanol obtained from [1-2H]acetaldehyde with different micro-organisms. Although only S-[1-2H]ethanol was formed, all the micro-organisms showed evidence of the existence of alcohol dehydrogenases with opposite stereospecificity.
Subject(s)
Acetaldehyde/metabolism , Bacteria/metabolism , Ethanol/metabolism , Fungi/metabolism , Deuterium , Gas Chromatography-Mass Spectrometry , Molecular ConformationABSTRACT
(13)C enrichments at C-3, C-4, C-5 and C-6 of canthin-6-one from cell cultures of Ailanthus altissima supplemented with [1-(13)C], [2-(13)C] and [1,2-(13)C] acetate, give evidence of the involvement of ketoglutarate as an intact precursor in the biosynthetic pathway.
ABSTRACT
The mechanism of 3-hydroxy epimerization of chenodeoxycholic acid by Clostridium perfringens was investigated in 3 alpha, 7 alpha-dihydroxy-[2,2,4,4-2H4]-, 3 alpha, 7 alpha-dihydroxy-[3 beta-2H]- and 3 beta, 7 alpha-dihydroxy-[3 alpha-2H]-5 beta-cholanoic acid transformations. Our findings rule out a dehydration-rehydration pathway and agree with a redox mechanism involving 3-oxochenodeoxycholic acid as intermediate.
Subject(s)
Chenodeoxycholic Acid/metabolism , Clostridium perfringens/metabolism , Bile Acids and Salts/metabolism , Chemical Phenomena , Chemistry , Deuterium , Oxidation-Reduction , StereoisomerismABSTRACT
The pathway of the maloalcoholic fermentation in Schizosaccharomyces pombe was investigated by a 1H-, 2H- and 13C-n.m.r.-spectroscopic study of hydrogen and deuterium distribution on the ethanol produced by S. pombe from L-malic acid in 2H2O and from L-[2-2H]malic acid. Our findings rule out a double-decarboxylation mechanism and agree with a pathway that involves acetaldehyde as intermediate.
Subject(s)
Ascomycota/metabolism , Ethanol/metabolism , Fermentation , Malates/metabolism , Schizosaccharomyces/metabolism , Magnetic Resonance SpectroscopyABSTRACT
Fifty-one strains of the genus Bifidobacterium have been found to accumulate indole-3-lactic acid in culture broth. The isolated metabolite was identified through mass and nuclear magnetic resonance spectroscopy. All the microorganisms tested, as resting cells, have been shown to be able to convert L-tryptophan into L-indole-3-lactic acid.
