TABLE 4.

Effects of organic solvents on the in vitro cis-trans isomerization of unsaturated fatty acids of crude membranes from P. oleovorans GPo12 and E. coli AM1095^a

Membrane sourceb and organic solvent	% Conversion to trans-9-hexadecenoic acidc
	Control (no isomerase)	Expt (isomer-ase added)
P. oleovorans GPo12
None	9	11
10% (vol/vol) methanol	11	23
10% (vol/vol) ethanol	12	32
0.1% (vol/vol) octanol	14	60
E. coli AM1095
None	0	6
10% (vol/vol) methanol	0	18
10% (vol/vol) ethanol	0	26
0.1% (vol/vol) octanol	0	56

^aCrude membranes of P. oleovorans GPo12 or E. coli AM1095 which contained 0.5 μmol of cis-9-hexadecenoic acid were incubated with 0.01 U of cis-trans isomerase and various organic solvents in a final assay volume of 0.5 ml (phosphate buffer [50 mM, pH 7.2]). After an incubation time of 60 min, the reaction mixture was analyzed for fatty acid composition as stated in Materials and Methods. Each value is the average of three independent experiments. 

^bCrude membranes were isolated from spheroplasts of P. oleovorans GPo12 and E. coli AM1095 as described in Materials and Methods. 

^cThe in vitro isomerization of membranes was expressed as the percentage of trans-9-hexadecenoic acid relative to the total amount of cis-9-hexadecenoic acid and trans-9-hexadecenoic acid.