TABLE 3.

Specificity of the cis-trans isomerase of P. oleovorans GPo12^a

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

^aThe 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. 

^bThe concentration of cis-unsaturated fatty acids used in the assay mixture was 1 mM. 

^cActivity determined with various fatty acids relative to the activity seen with free cis-9-hexadecenoic acid (100%) to activity determined with various fatty acids. 

^dThe 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.