Biosynthesis of wax esters in cell-free preparations of euchaeta norvegica

Abstract

1. 1. Wax esters account for 60% of the total lipid in Euchaeta; the total lipid accounts for 20% of the dry weight. 2. 2. Cell-free preparations supplemented with magnesium ions, coenzyme A and ATP incorporate ( 14C) palmitic acid more readily into was esters than into triglycerides. 3. 3. Incorporation of fatty acid into was esters is a heat-labile process, linear for 20 hr at 10°C and optimally active at 25°C. 4. 4. Incorporation of ( 14C) palmitic acid into wax esters is markedly stimulated by adding unlabelled oleyl alcohol; incorporation into triglycerides is scarcely stimulated by adding a variety of acyl acceptors. 5. 5. ( 14C) Hexadecanol is readily incorporated into wax esters in the cell-free system but unlabelled oleic acid does not markedly stimulate the incorporation. 6. 6. ( 14C) Palmityl coenzyme A is incorporated into wax esters in the cell-free system in the absence of added cofactors. Such incorporation is stimulated by NADPH after which increased levels of radioactivity are present in fatty alcohol recovered from wax ester. 7. 7. The data are discussed in terms of rate-limiting steps in the biosynthesis of wax esters.