The biosynthesis of cyclopropane and cyclopropene fatty acids in plant tissues.

The biosynthesis of cyclopropane and cyclopropene fatty acids was investigated in seeds of several species of the order Malvales, including species with a high content of sterculic acid, a high content of malvalic acid, and a low content of these cyclopropene fatty acids. The fatty acid composition of the lipids in young and developing seeds is compared with particular attention to variations in cyclopropane and cyclopropene fatty acid contents.Incubation studies employing several(14)C compounds indicate that the methyl group of methionine is the most likely precursor of the ring-methylene carbon. A pathway for the synthesis of the cyclopropane and cyclopropene fatty acids is postulated. The origin of malvalic acid is also considered.