TABLE 3.
Specificity of the cis-trans isomerase of P. oleovorans GPo12a
Substrateb | Relative activity (%)c |
---|---|
cis-9-Tetradecenoic acid | 0 |
cis-9-Hexadecenoic acid | 100 |
Methyl cis-9-hexadecenoate | 0 |
cis-6-Octadecenoic acid | 0 |
cis-7-Octadecenoic acid | 0 |
cis-9-Octadecenoic acid | 12 |
cis-11-Octadecenoic acid | 102 |
cis-13-Octadecenoic acid | 0 |
cis-11-Eicosenoic acid | 18 |
cis-13-Eicosenoic acid | 103 |
Pure phospholipidsd | 0 |
The substrate range of the cis-trans isomerase was analyzed by incubating the enzyme in 50 mM phosphate buffer (7.2) and various cis-unsaturated fatty acids and determining the rate of appearance of trans-unsaturated fatty acids. Each value represents an average of three independent experiments.
The concentration of cis-unsaturated fatty acids used in the assay mixture was 1 mM.
Activity determined with various fatty acids relative to the activity seen with free cis-9-hexadecenoic acid (100%) to activity determined with various fatty acids.
The phospholipids were isolated from Pseudomonas and E. coli cells by chloroform-methanol extraction and subsequently purified by acetone precipitation as described in Materials and Methods. Both sonicated dispersions and multilamellar phospholipid vesicles were used in the assay.