Characterization of aerobic desaturation of palmitic acid using resting cells of Alcaligenes faecalis
Kshirsagar, S.S.; Nair, P.M.
Indian Journal of Biochemistry and Biophysics 16(4): 227-231
1979
ISSN/ISBN: 0301-1208 PMID: 535934 Document Number: 149574
The desaturase activity in the gram-negative bacterium, A. faecalis, was dependent on the age of culture. The monounsaturated fatty acid formation was minimum at end-log phase and increased during active-log phase. It started decreasing at end-log and reduced considerably in the early stationary phase. In the late stationary phase there was only a negligible incorporation of the labeled substrate palmitic acid in the bacterial lipids. The enzyme system in the resting cells was also highly temperature-sensitive. The desaturase activity was maximum at the lowest temperature studied, i.e., 25.degree. C, and minimum at 35.degree. C. The O2 requirement for the desaturation was confirmed by the anaerobic experiment. The desaturation was considerably less under the anaerobic condition than in the aerobic experiment. The possibility of breakdown and resynthesis was ruled out by decarboxylation of the monounsaturated fatty acid fraction, which gave 90% counts as radioactive 14CO2. Ferrous ion was an essential cofactor in desaturation. Cytochrome P-450 was not involved and flavine was not a cofactor for the desaturation.