Fatty acid ethyl ester synthase, an enzyme for nonoxidative ethanol metabolism, is present in serum after liver and pancreatic injury

Fatty acid ethyl esters (FAEE), esterification products of ethanol and fatty acids, have been implicated as mediators of ethanol-induced organ damage. Because cytosolic enzymes such as aspartate aminotransferase, lipase, and amylase appear in the blood after liver or pancreatic damage, we hypothesized that FAEE synthase, which is both cytosolic and membrane bound, is also released into the blood of patients with liver or pancreatic disease. We used a method involving thin-layer chromatography coupled with gas chromatography-mass spectrometry to reliably identify and quantify FAEE. In this study, we demonstrated that patients with liver or pancreatic disease release FAEE synthase into their plasma in amounts proportional to the amount of aspartate aminotransferase (r = 0.78), amylase (r = 0.65), and lipase (r = 0.63). These data indicate that liver and pancreatic damage results in release of FAEE synthase into the blood. The presence of FAEE synthase in plasma permits nonoxidative ethanol metabolism in the plasma.