Abstract
1. Simultaneous oxidation of C14-methyl-labeled acetate, and unlabeled malate or fumarate and α-ketoglutarate results in entrapment of labeled carbon in the C4-dicarboxylic acids, but not in α-ketoglutarate, although all substrates are utilized at comparable rates. 2. A large endogenous reduction of all C4-dicarboxylic acids (fumarate, oxalacetate, and malate) to succinate is observed under aerobic conditions, and when vigorous oxidation is proceeding. This effect occurs with both freshly harvested young (18 hour) cells and stored (2 week) cells. 3. This reduction can be considerably minimized under high oxygen tensions. 4. The quantitative concordance of these results with a Thunberg-Knoop cyclic mechanism for acetate oxidation is shown. Possible alternative C4 products formed prior to succinate are not completely excluded, but it appears that the cells can utilize the succinate condensation as a major pathway in acetate oxidation.
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Selected References
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- AJL S. J. Acetic acid oxidation by Escherichia coli and Aerobacter aerogenes. J Bacteriol. 1950 Apr;59(4):499–507. doi: 10.1128/jb.59.4.499-507.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- AJL S. J., KAMEN M. D. Studies on the mechanism of acetate oxidation by Escherichia coli. J Biol Chem. 1951 Apr;189(2):845–857. [PubMed] [Google Scholar]
- Krebs H. A. The role of fumarate in the respiration of Bacterium coli commune. Biochem J. 1937 Nov;31(11):2095–2124. doi: 10.1042/bj0312095. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TOLBERT N. E., CLAGETT C. O., BURRIS R. H. Products of the oxidation of glycolic acid and L-lactic acid by enzymes from tobacco leaves. J Biol Chem. 1949 Dec;181(2):905–914. [PubMed] [Google Scholar]