Desaturation of saturated fatty acids by rat liver microsomes
- 16 Downloads
A method was developed for the rapid determination of the initial velocity of the desaturation of saturated fatty acids. In the reaction, DPNH was a more efficient electron donor than TPNH. Fatdeficient rats have a 2.5-fold greater level of acyl desaturase per milligram of liver microsomal protein than did animals fed lab chow. Increasing the chain length of the acyl substrate from 10∶0 to 18∶0 increases the rate of monoene formation, but 19∶0 is desaturated at a rate lower than that for 15∶0. The energy of activation (Ea) for the overall desaturation reaction has been determined for 12∶0 through 19∶0. The Ea values for desaturation of 13∶0 and 16∶0 are markedly lowr than for the other acids. An interaction between the alkyl chain of the substrate and polyunsaturated acids of the microsomal membrane-bound phospholipids is postulated to explain the recurring 3-carbon pattern of the relative reaction rates of the various acyl substrates.
KeywordsDesaturase Activity Endogenous Fatty Acid TPNH DPNH Acyl Activation
Unable to display preview. Download preview PDF.
- 3.Brenner, R., and R. Peluffo, Ibid. 241:5213–5219 (1966).Google Scholar
- 9.Beisenherb, G., H. J. Boltze, T. Bucher, R. Czok, K. H. Garbade, E. Meyer-Arendt and G. Pfleiderer, Z. Naturforsch. 8B:555 (1953).Google Scholar
- 12.Glass, R. L., and S. W. Christopherson, Chem. Phys. Lipids, in press.Google Scholar
- 13.Graff, G., Y. L. Marcel and R. T. Holman, J. Chromatog. Sci. 7:298–299 (1969).Google Scholar