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Pyruvate decarboxylase catalyzes decarboxylation of branched-chain 2-oxo acids but is not essential for fusel alcohol production by Saccharomyces cerevisiae.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Schure, Eelko G. Ter Flikweert, Marcel T. Dijken, Johannes P. Van Pronk, Jack T. Verrips, C. Theo |
| Copyright Year | 1998 |
| Abstract | The fusel alcohols 3-methyl-1-butanol, 2-methyl-1-butanol, and 2-methyl-propanol are important flavor compounds in yeast-derived food products and beverages. The formation of these compounds from branched-chain amino acids is generally assumed to occur via the Ehrlich pathway, which involves the concerted action of a branched-chain transaminase, a decarboxylase, and an alcohol dehydrogenase. Partially purified preparations of pyruvate decarboxylase (EC 4.1.1.1) have been reported to catalyze the decarboxylation of the branched-chain 2-oxo acids formed upon transamination of leucine, isoleucine, and valine. Indeed, in a coupled enzymatic assay with horse liver alcohol dehydrogenase, cell extracts of a wild-type Saccharomyces cerevisiae strain exhibited significant decarboxylation rates with these branched-chain 2-oxo acids. Decarboxylation of branched-chain 2-oxo acids was not detectable in cell extracts of an isogenic strain in which all three PDC genes had been disrupted. Experiments with cell extracts from S. cerevisiae mutants expressing a single PDC gene demonstrated that both PDC1- and PDC5-encoded isoenzymes can decarboxylate branched-chain 2-oxo acids. To investigate whether pyruvate decarboxylase is essential for fusel alcohol production by whole cells, wild-type S. cerevisiae and an isogenic pyruvate decarboxylase-negative strain were grown on ethanol with a mixture of leucine, isoleucine, and valine as the nitrogen source. Surprisingly, the three corresponding fusel alcohols were produced in both strains. This result proves that decarboxylation of branched-chain 2-oxo acids via pyruvate decarboxylase is not an essential step in fusel alcohol production. |
| File Format | PDF HTM / HTML |
| DOI | 10.1128/aem.64.4.1303-1307.1998 |
| Alternate Webpage(s) | http://marcelf.home.xs4all.nl/Thesis/Chapter8.pdf |
| Alternate Webpage(s) | http://aem.asm.org/content/64/4/1303.full.pdf |
| PubMed reference number | 9546164 |
| Alternate Webpage(s) | https://doi.org/10.1128/aem.64.4.1303-1307.1998 |
| Journal | Medline |
| Volume Number | 64 |
| Issue Number | 4 |
| Journal | Applied and environmental microbiology |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |