Enzymatic synthesis of cyclopropane fatty acids catalyzed by bacterial extracts.

The pioneering studies of Hofmann and co-workers on the lipids of lactobacilli led to the discovery of a 19 carbon fatty acid containing a cyclopropane ring (l-5). This acid was characterized as cis-11 ,12-methyleneoctadecanoic acid and was given the trivial name, lactobacillic acid. A 17 carbon fatty acid from Escherichia coli was described by Dauchy and Asselineau (6) and characterized as cis-9, lo-methylenehexadecanoic acid by Kaneshiro and Marr (7). Whole cell experiments demonstrated the importance of the methyl group of methionine as a 1 carbon unit for the conversion of 16 and 18 carbon monounsaturated fatty acids to 17 and 19 carbon cyclopropane acids, respectively (4, 8-10). We wish to report our studies on the enzymatic synthesis of cyclopropane fatty acids’ catalyzed by cell-free extracts prepared from the gram-negative aerobe, Serratia marcescens, and the gram-positive anaerobe, Clostridium butyricum. -1 preliminary account has appeared (11).