PMID:2644239
| Citation |
Zhu, Y and Lin, EC (1989) L-1,2-propanediol exits more rapidly than L-lactaldehyde from Escherichia coli. J. Bacteriol. 171:862-7 |
|---|---|
| Abstract |
Catabolism of the six-carbon compound L-fucose results in formation of dihydroxyacetone phosphate (C-1-to-C-3 fragment) and L-lactaldehyde (C-4-to-C-6 fragment) as intermediates. The fate of lactaldehyde depends on the respiratory growth conditions. Aerobically, lactaldehyde is oxidized to L-lactate by an NAD-linked dehydrogenase (ald product). L-Lactate, in turn, is converted to pyruvate, which enters the general metabolic pool. Anaerobically, lactaldehyde is reduced to L-1,2-propanediol by an NADH-linked oxidoreductase (fucO product). L-1,2-Propanediol is excreted as a terminal fermentation product. In a previous study, we showed that retention of the C-4-to-C-6 fragment of fucose depended on the competition for lactaldehyde by aldehyde dehydrogenase and propanediol oxidoreductase (Y. Zhu and E.C.C. Lin, J. Bacteriol. 169:785-789, 1987). In this study, we compared the wild-type strain and isogenic mutant strains defective in ald, fucO, or both for ability to accumulate radioactivity when incubated with fucose labeled at either the C-1 or the C-6 position. The results showed that although blocking the oxidation of lactaldehyde prevented its assimilation, rapid exit of the 3-carbon unit occurred only when the compound was reduced to propanediol. Moreover, growth experiments on fucose indicated that a double ald fucO mutant accumulated inhibiting concentrations of lactaldehyde. The inner cell membrane therefore appears to be much more permeable to the 3-carbon alcohol than to the 3-carbon aldehyde. The almost instantaneous exit of propanediol appears to be a facilitated process. |
| Links | |
| Keywords |
Aldehydes/metabolism; Biological Transport; Escherichia coli/genetics; Escherichia coli/metabolism; Genes, Bacterial; Genes, Regulator; Genotype; Mutation; Phenotype; Propylene Glycol; Propylene Glycols/metabolism; Restriction Mapping; Species Specificity |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.