The enzymatic synthesis of wax esters by a microsomal preparation from the honeybee Apis mellifera L.

Abstract

A microsomal preparation obtained from the abdomens of the honeybee Apis mellifera L. incorporated long chain primary alcohols, fatty acids, and the acyl group from acyl-CoA into cuticular wax monoesters. The incorporation of [1 - 14C]-palmitate into monoester was stimulated by ATP, CoA, and MgCl 2, and the addition of palmitoyl-CoA caused a five fold increase in monoester synthesis using [R- 3H]-tetracosanol as the labelled substrate. This indicated that the mechanism of monoester synthesis involved the transfer of an acyl group from acyl-CoA to a primary alcohol. The addition of palmitoyl-CoA at concentrations up to 100 μM caused an increase in the rate of monoester synthesis, whereas at concentrations above 100 μM, palmitoyl-CoA markedly inhibited monoester formation. An apparent K m for tetracosanol was calculated from a double reciprocal plot to be 9 × 10 −4 M. Although the naturally occurring primary alcohols in the monoesters of the cuticular wax from the honeybee range in chain length from C 24 to C 32, labelled primary alcohols of 16, 18, 24 and 28 carbons were readily incorporated into monoester, with the C 16 and C 18 components incorporated at higher rates then the C 24 and C 28 homologues. A C 27 secondary alcohol was not incorporated into wax esters.