| Title: | Acetone formation in the Vibrio family: a new pathway for bacterial leucine catabolism |
| Author(s): | Nemecek-Marshall M; Wojciechowski C; Wagner WP; Fall R; |
| Address: | "Department of Chemistry and Biochemistry, and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309-0215, USA" |
| DOI: | 10.1128/JB.181.24.7493-7499.1999 |
| ISSN/ISBN: | 0021-9193 (Print) 1098-5530 (Electronic) 0021-9193 (Linking) |
| Abstract: | "There is current interest in biological sources of acetone, a volatile organic compound that impacts atmospheric chemistry. Here, we determined that leucine-dependent acetone formation is widespread in the Vibrionaceae. Sixteen Vibrio isolates, two Listonella species, and two Photobacterium angustum isolates produced acetone in the presence of L-leucine. Shewanella isolates produced much less acetone. Growth of Vibrio splendidus and P. angustum in a fermentor with controlled aeration revealed that acetone was produced after a lag in late logarithmic or stationary phase of growth, depending on the medium, and was not derived from acetoacetate by nonenzymatic decarboxylation in the medium. L-Leucine, but not D-leucine, was converted to acetone with a stoichiometry of approximately 0.61 mol of acetone per mol of L-leucine. Testing various potential leucine catabolites as precursors of acetone showed that only alpha-ketoisocaproate was efficiently converted by whole cells to acetone. Acetone production was blocked by a nitrogen atmosphere but not by electron transport inhibitors, suggesting that an oxygen-dependent reaction is required for leucine catabolism. Metabolic labeling with deuterated (isopropyl-d(7))-L-leucine revealed that the isopropyl carbons give rise to acetone with full retention of deuterium in each methyl group. These results suggest the operation of a new catabolic pathway for leucine in vibrios that is distinct from the 3-hydroxy-3-methylglutaryl-coenzyme A pathway seen in pseudomonads" |
| Keywords: | "Acetone/*metabolism Kinetics Leucine/*metabolism Models, Biological Models, Chemical Photobacterium/metabolism Vibrio/metabolism Vibrionaceae/*metabolism;" |
| Notes: | "MedlineNemecek-Marshall, M Wojciechowski, C Wagner, W P Fall, R eng Research Support, U.S. Gov't, Non-P.H.S. 1999/12/22 J Bacteriol. 1999 Dec; 181(24):7493-9. doi: 10.1128/JB.181.24.7493-7499.1999" |
