Abstract
The syntheses and hydrolyses of wax esters and cholesterol esters in the plasma and hepatopancreas of carp were compared with those of blue crab, crayfish and man. The incorporations of both [1-14C]palmitic acid and [1-14C]cetyl alcohol into wax esters as well as of [4-14C]cholesterol into cholesterol esters in all the plasma were observed. Comparing the substrates, [I-C14]cetyl alcohol was more remarkably incorporated into wax esters than [1-14C]palmitic acid. And also wax esters and cholesterol esters were synthesized by the hepatopancreas preparations of blue crab and crayfish.
The hydrolyzing activities of cetyl [1-14C]palmitate, [4-14C]cholesteryl oleate and glycerol tri[1-14C]palmitate in every plasma were examined, and it was found that the activities in plasma were much lower than those in hepatopancreas.
Since large amounts of [1-14C]cetyl alcohol are incorporated into wax esters of plasma, it is suggested that a kind of enzyme, which catalyze the transfer of fatty acids in lecithin to the acyl moiety of wax esters, might be present in the plasma. Such enzyme would be tentatively called lecithin: alcohol acyltransferase-type.
