Tsujita T, Sumiyoshi M, Okuda H
Central Research Laboratory, School of Medicine, Ehime University, Onsen-gun, Japan.
Lipids. 1999 Nov;34(11):1159-66. doi: 10.1007/s11745-999-0467-4.
The synthesis/hydrolysis of wax esters was studied in an aqueous solution using purified rat pancreatic lipase, porcine pancreatic carboxylester lipase, and Pseudomonas fluorescens lipase. The equilibrium between wax ester synthesis and hydrolysis favored ester formation at neutral pH. The synthesizing activities were measured using free fatty acid or triacylglycerol as the acyl donor and an equimolar amount of long-chain alcohol as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with these lipases, wax ester was synthesized, in a dose- and time-dependent manner, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was about 0.9/0.1. These lipases catalyzed the hydrolysis of palmityl oleate emulsified with gum arabic, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was also about 0.9/0.1. The apparent equilibrium ratio of wax ester/free fatty acid catalyzed by lipase depended on incubation pH and fatty alcohol chain length. When equimolar amounts of trioleoylglycerol and fatty acyl alcohol were incubated with pancreatic lipase, carboxylester lipase, or P. fluorescens lipase, wax esters were synthesized dose-dependently. These results suggest that lipases can catalyze the synthesis of wax esters from free fatty acids or through degradation of triacylglycerol in an aqueous medium.
使用纯化的大鼠胰腺脂肪酶、猪胰腺羧酸酯脂肪酶和荧光假单胞菌脂肪酶，在水溶液中研究了蜡酯的合成/水解。在中性pH条件下，蜡酯合成与水解之间的平衡有利于酯的形成。使用游离脂肪酸或三酰甘油作为酰基供体，以及等摩尔量的长链醇作为酰基受体来测定合成活性。当用阿拉伯胶乳化的油酸和十六醇与这些脂肪酶一起孵育时，蜡酯以剂量和时间依赖性方式合成，棕榈油酸酯/游离油酸的表观平衡比约为0.9/0.1。这些脂肪酶催化用阿拉伯胶乳化的棕榈油酸酯的水解，棕榈油酸酯/游离油酸的表观平衡比也约为0.9/0.1。脂肪酶催化的蜡酯/游离脂肪酸的表观平衡比取决于孵育pH和脂肪醇链长度。当等摩尔量的三油酰甘油和脂肪酰醇与胰腺脂肪酶、羧酸酯脂肪酶或荧光假单胞菌脂肪酶一起孵育时，蜡酯呈剂量依赖性合成。这些结果表明，脂肪酶可以在水性介质中催化从游离脂肪酸合成蜡酯或通过三酰甘油的降解来合成蜡酯。
