Figure 3.

Fatty acid specificity of the purified recombinant ACS4. (A) Enzyme activity was determined by the spectrophotometric method with 1 μg of the purified enzyme and the standard reaction mixture, except that various saturated and unsaturated fatty acids (final concentration = 0.1 mM) were used. Enzyme activity is expressed as a percentage of that obtained with palmitate as a substrate (21.1 μmol per min per mg). The data are the mean ± SD of triplicate experiments. Saturated fatty acids: 8:0, octanoic acid; 10:0, decanoic acid; 12:0, lauric acid; 14:0, myristic acid; 16:0, palmitic acid; 18:0, stearic acid; 20:0, arachidic acid; 22:0, docosanoic acid. Unsaturated fatty acids: 14:1, myristoleic acid; 16:1, palmitoleic acid; 18:1, oleic acid; 18:2, linoleic acid; 18:3, linolenic acid; 20:4, arachidonic acid; 20:5, eicosapentaenoic acid; 22:6, docosahexaenoic acid. (B) Lineweaver–Burk plots of ACS activity for arachidonate, eicosapentaenoate, and palmitate. Assays were performed with the indicated fixed concentrations of arachidonate, eicosapentaenoate, and palmitate, as described above. Data points represent the mean of three determinations obtained in one experiment.