Substrate specificity for the synthesis of cyclic Fatty acids by a flaxseed extract.
12-Oxo-cis-10,15-phytodienoic acid is an enzymic product obtained from incubations of (9, 12, 15)-linolenic acid with extracts of flaxseed (Linum usitatissimum L.). 13-l-Hydroperoxy-cis-9, 15-trans-11-octadecatrienoic acid, a product of lipoxygenase catalysis, was an intermediate in the enzymic synthesis of 12-oxo-cis-10, 15-phytodienoic acid from (9, 12, 15)-linolenic acid. Substrate specificity studies showed that n-3,6,9 unsaturation was an absolute requirement for conversion of polyunsaturated fatty acids into analogous products containing a cyclopentenone ring. Fatty acids with 18, 20, or 22 carbons that satisfied this requirement were effective substrates. The optimum activity of the enzyme from flaxseed was at pH 7.2.
Vick
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BA
United States Department of Agriculture, Science and Education Administration, Agricultural Research, Department of Biochemistry, North Dakota State University, Fargo, North Dakota 58105.
Zimmerman
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DC