Acyl coenzyme A:retinol acyltransferase activity and the vitamin A content of polar bear (Ursus maritimus) liver.
Acyl coenzyme A:retinol acyltransferase activity was identified in the microsomes from a polar bear liver. The highest rate of in vitro retinol esterification was 821 pmol/min/mg microsomal protein. The in vitro esterification rate displayed a small dependence upon the concentration of exogenous protein (bovine serum albumin) and even less on the concentration of sulfhydryl-reducing agent (dithiothreitol). Vitamin A was present in the liver at a concentration of 8050 micrograms/g tissue, with 98% of the vitamin in its ester form. Retinyl palmitate was 37.3% of the total liver retinyl esters, while retinyl oleate represented 20.9%, stearate 12.8%, and linoleate 7.7%.
D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D000836:Animals, Zoo; D002335:Carnivora / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D051142:Retinol O-Fatty-Acyltransferase; D001503:Ursidae / Q000378:metabolism*; D014801:Vitamin A / Q000032:analysis*
D014801:Vitamin A; D000217:Acyltransferases; D051142:Retinol O-Fatty-Acyltransferase