Identification of cis-9,10-methylenehexadecanoic acid in submitochondrial particles of bovine heart

Submitochondrial particles of bovine heart were hydrolyzed by phospholipase Al and the products were analyzed by liquid chromatography electrospray io nization-mass spectrometry. We found a fatty acid with a molecular mass of 268 Da and a retention time longer than that of linoleic acid. Next, we syn thesized organically cis-9,10-methylenehexadecanoic acid, which has a molec ular mass similar to that of the extracted fatty acid, and characterized it s high performance liquid chromatography and gas chromatography-mass spectr ometry profiles. Using these data we were able to identify endogenous cis-9 ,10-methylenehexadecanoic acid in rat and human heart and liver tissues tha t had been hydrolyzed by phospholipase A(2). This fatty acid was not detect ed in tissue extracts that had not been hydrolyzed by phospholipase A(2). S imilar amounts of cis-9,10-methylenehexadecanoic acid were measured in tiss ue extracts after total hydrolysis. These results suggest that cis-9, 10-me thylenehexadecanoic acid is a fatty acid component, in the sn-2 position, o f phospholipids in some mammalian tissue. (C) 1999 Published by Elsevier Sc ience B.V. All rights reserved.