Fatty acid ethyl ester synthase catalyzes the esterification of ethanol to cocaine

Fatty acid ethyl esters (FAEE), esterification products of ethanol and fatty acids, have been implicated as mediators of ethanol induced organ damage. It has been shown that FAEE synthase, the enzyme responsible for the formation of FAEE, is present selectively in the organs damaged by ethanol abuse. Cocaethylene is a cocaine metabolite generated in the presence of ethanol which has been established as enhancing cocaine toxicity. In the present study we show that purified FAEE synthase also catalyzes the formation of cocaethylene. A linear relationship (r = 0.998) was demonstrated between the amount of purified FAEE synthase (microgram) and cocaethylene synthesis (nmol/hr). We further showed a correlation (r = 0.804) between the two enzyme activities in selected tissues. These findings provide evidence that purified FAEE synthase has cocaethylene synthetic ability and FAEE synthase may be responsible for a portion of cocaethylene synthesis in vivo.