Acetone powder preparations from the roots of white mustard (Sinapis alba L) seedlings efficiently catalyse the esterification of [1-14C]n-hexadecanol in the presence of tripalmitoylglycerol as the fatty acid source. Free palmitic acid as well as mono- and dipalmitoylglycerols are much less effective which indicates that a direct acyl transfer from triacylglycerols to long-chain alcohols takes place. The formation of wax esters was also followed using tri-[1-14C]palmitoylglycerol and unlabelled alcohol. In this reaction straight-chain, saturated and unsaturated, primary alcohols as well as an isoprenoid alcohol--phytol can be utilized as acyl acceptors. Of the saturated straight-chain alcohols, C20 alcohol was esterified most efficiently. Triacylglycerols containing fatty acids C12-C22, both saturated and unsaturated, can serve as acyl sources. Among triacylglycerols containing saturated fatty acids trimyristoyl- and tripalmitoylglycerols are the best acyl donors.