Cis-9-hexadecenoic acid,

Fig. 1 HPLC of free fatty acids. Column SUPELCOSIL LC 18. 25 cm X 4.6-mm ID. (5fi) mobile phase tetrahydrofuran/acetonitrile/0.1% phosphoric acid, pH 2.2 (21.6 50.4 28.0) flow rate 1.5 ml/min temperature 35°C detection at 220 nm sample concentration 1-2 mg/ml per component. 16 1 (cis) = cis-9-hexadecenoic acid (cis-palmitoleic acid) 16 1 (trans) = trans-9-hexadecenoic acid (trans-palmitoleic acid) 18 0 = octadecanoic acid (stearic acid) 18 1 (cis) = cw-9-octadecenoic acid (oleic acid) 18 1 (trans) = trans-9-octadecenoic acid (elaidic acid) 18 2 (cis) = cis-9-cis-12-ctadecadienoic acid (linoleic acid) 18 2 (trans) = trans-9-trans-12-octadecadienoic acid (linolelaidic acid) 18 3 (cis) = cis-9-cis-2-cis-15-octadecatrienoic acid (linolenic acid).

Hexadec-9-enoic acid methyl ester, (Z) ci.s-9-Hexadecenoic acid methyl ester Methyl Palmitoleate... 

Based on the postulated common metabolic pathway involved in DOD and TOD formation by PR3, it was assumed that palmitoleic acid containing a singular C9 cis double bond (a common structural property shared by oleic and ricinoleic acids), could be utilized by PR3 to produce hydroxy fatty acid. Bae et al. (2007) reported that palmitoleic acid could be utilized as a substrate for the production of hydroxy fatty acid by PR3. Structural analysis of the major product produced from palmitoleic acid by PR3 confirmed that strain PR3 could introduce two hydroxyl groups on carbon 7 and 9 with shifted migration of 9-cis double bond into 8-tram configuration, resulting in the formation of 7,10-dihydroxy-8( )-hexadecenoic acid (DHD) (Fig. 31.3).The time course study of DHD production showed that DHD formation was time-dependently increased, and peaked at 72 h after the addition of palmitoleic acid as substrate. However, production yield of DHD (23%) from palmitoleic acid was relatively low when compared to that of DOD (70%) from oleic acid (Hou and Bagby, 1991). 

Okuyama et al.12711 purified the cis-trans isomerase from Pseudomonas sp. E-3 and characterized the enzyme catalyzing cis-trans isomerization toward 9-hexadecenoate. It catalyzes the cis-to-trans conversion of a double bond of cis-mono-unsaturated fatty acids with carbon chain lengths of 14,15,16, and 17 at positions 9,10, or 11, but not at 6 or 7 the enzyme shows a strict specificity for both the position of the double bond and the chain length of the fatty acid. A similar enzyme was also discovered by Witholt and coworkers, which was purified from the periplasmic fraction of Pseudomonas oleovorans12721. Not only 9-cis-hexadecenoate but also 11-cis-octadece-noate were found to serve as substrates of the enzyme. Moreover, the enzyme acted only on free unsaturated fatty acids and not on esterified fatty acids in contrast to the enzyme from Pseudomonas sp. E-3. Therefore, the Pseudomonas oleovorans enzyme differs from the enzyme of Pseudomonas sp. E-3 in substrate specificity, although both are monomeric enzymes with a molecular mass of about 80 kDa. The cis-trans isomerases are expected to be useful for biotransformation of unsaturated fatty acids. 

Identification and Characterization of 9-cis-Hexadecenoic Acid Cis-Trans Isomerase of Pseudomonas Sp. Strain E-3. 

The fatty acid composition of glycerolipids from cyanobacteria was studied first by Holton et al. (1964) in A. nidulans, and by Levin et al. (1964) in A. variabitis. Subsequent analyses have characterized the fatty acids from a number of cyanobacteria. The fatty acids thus far known to be present in cyanobacteria are hexadecanoic acid or palmitic acid (16 0), A -cis-hexadecenoic acid or palmitoleic acid (16 1), hexadeca-dienoic acid (double bond positions undetermined) (16 2), octadecanoic agi 2° stearic acid (18 0), A -cis-octadecenoic acid or glj Cj gcid (18 1), A -cis-ootadecadienoic acid or linoleic acid (18 2, 9 2 -"f" ... 

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