Ball M D, Furr H C, Olson J A
Comp Biochem Physiol B. 1986;84(4):513-7. doi: 10.1016/0305-0491(86)90115-x.
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%.
在北极熊肝脏微粒体中鉴定出了酰基辅酶A：视黄醇酰基转移酶活性。体外视黄醇酯化的最高速率为821皮摩尔/分钟/毫克微粒体蛋白。体外酯化速率对外源蛋白（牛血清白蛋白）浓度的依赖性较小，对巯基还原剂（二硫苏糖醇）浓度的依赖性更小。肝脏中维生素A的浓度为8050微克/克组织，其中98%的维生素为酯形式。棕榈酸视黄酯占肝脏视黄酯总量的37.3%，油酸视黄酯占20.9%，硬脂酸视黄酯占12.8%，亚油酸视黄酯占7.7%。
