Cholinesterase‐catalyzed resolution of D , L ‐carnitine

An enzymatic method for the preparative resolution of racemic carnitine (whose L ‐isomer and its acyl‐derivatives have numerous therapeutical applications) has been developed. It is based on our finding that electriceel acetylcholinesterase hydrolyzes the D ‐ but not the L ‐isomer of acetylcarnitine. (Another cholinesterase tested, horse serum butyrylcholinesterase, is also stereospecific and hydrolyzes only the L ‐isomer of butyrylcarnitine.) Acetylcholinesterase, covalently attached to alumina, was employed for the resolution of D , L ‐carnitine; the latter was first chemically acetylated, then stereoselectively hydrolyzed with the immobilized enzyme, and finally the acetyl‐ L ‐carnitine and D ‐carnitine produced were separated by ion‐exchange chromatography. Gram quantities of D , L ‐carnitine were thereby resolved.