Biosynthesis and hydrolysis of cholesteryl esters by rat skin subcellular fractions. Regulation by prostaglandins.
Biosynthesis and hydrolysis of cholesteryl esters by rat skin subcellular fractions. Regulation by prostaglandins.
复制标题
大鼠皮肤亚细胞组分的胆固醇酯的生物合成和水解。
作者：
V. Ziboh;M. A. Dreize
研究了正常和必需脂肪酸缺乏大鼠皮肤中参与胆固醇酯合成和水解的酶的性质和亚细胞分布。胆固醇分解酶的大部分活性与12000 g和105000 g颗粒部分相关。酶反应对ATP和CoA的依赖性表明，大鼠皮肤对胆固醇的酯化是由脂肪酰基-CoA-胆固醇酰基转移酶（EC 2.3.1. -）介导的。另一方面，胆固醇酯水解酶（EC www.example.com）的大部分活性位于105000g上清液级分中。虽然在必需脂肪酸缺乏大鼠的皮肤制备物中胆固醇分解酶的活性升高，但水解酶的活性显著降低。这些观察结果可以部分解释这些动物皮肤中甾醇酯浓度升高的原因。低浓度的前列腺素E（2）对胆固醇分解酶的活性有明显的抑制作用，而在相似浓度下对水解酶的活性没有影响。然而，在高浓度下，前列腺素E（2）对水解酶的活性有中等的刺激作用。这些结果表明，这种物质在调节该组织中甾醇酯的产生中可能具有生理作用。
The properties and subcellular distribution of the enzymes involved with the synthesis and hydrolysis of cholesteryl esters were investigated in skin of normal and essential fatty acid-deficient rats. Most of the activity of the cholesterol-esterifying enzyme(s) is associated with the 12000g and 105000g particulate fractions. The dependence of the enzyme reaction on ATP and CoA suggests that the esterification of cholesterol by rat skin is mediated by a fatty acyl-CoA-cholesterol acyltransferase (EC 2.3.1.-). On the other hand, most of the activity of the cholesteryl ester hydrolase (EC 3.1.1.13) is localized in the 105000g supernatant fraction. Although the activity of the cholesterol-esterifying enzyme(s) was elevated in skin preparations from essential fatty acid-deficient rats, the activity of the hydrolase was significantly decreased. These observations may explain in part the elevated concentrations of sterol esters in the skin of these animals. Prostaglandin E(2) at low concentrations exerted marked inhibitory effect on the activity of the cholesterol-esterifying enzyme(s), whereas no effect was observed on the activity of the hydrolase at similar concentrations. However, at high concentrations prostaglandin E(2) exerted moderate stimulatory effect on the activity of the hydrolase. These results suggest a possible physiological role of this substance in regulating the production of sterol esters in this tissue.