Mathias P M, Harries J T, Muller D P
J Lipid Res. 1981 Jan;22(1):177-84.
Studies have been carried out to determine the maximal solubilization of cholesteryl oleate and tocopheryl acetate within mixed bile salt-fatty acid micelles and to establish reproducible assays for pancreatic esterase activity using these micellar substrates. At pH 8.5, using 30 mM sodium taurocholate and 10 mM oleic acid, reproducible micellar solutions of the esters could be prepared giving micellar concentrations of 0.4 mM and 0.1 mM for tocopheryl acetate and cholesteryl oleate, respectively. Conditions were then optimized to estimate pancreatic esterase activity using these micellar-solubilized substrates. Maximal activity was obtained at pH 8.5 with 2-4 mM oleic acid and 15-30 mM sodium taurocholate, and gave coefficients of variation for the assays of 7.4% and 20.2% using tocopheryl acetate and cholesteryl oleate, respectively, as substrates. Micellar-solubilized cholesteryl oleate and tocopheryl acetate, together with a non-micellar system using p-nitrophenyl acetate, were used to estimate esterase activity in human duodenal aspirates and rat pancreatic homogenates. Esterase activity in children with cystic fibrosis was greatly reduced and paralleled tryptic and pancreatic lipase activity, which suggested that the esterase activity was pancreatic in origin. The results of this study, therefore, provide a basis for future investigations concerned with the hydrolysis and absorption of dietary esters.
已开展多项研究，以确定胆固醇油酸酯和生育酚乙酸酯在混合胆盐 - 脂肪酸胶束中的最大增溶作用，并建立使用这些胶束底物测定胰酯酶活性的可重复检测方法。在pH 8.5条件下，使用30 mM牛磺胆酸钠和10 mM油酸，可制备出酯的可重复胶束溶液，其中生育酚乙酸酯和胆固醇油酸酯的胶束浓度分别为0.4 mM和0.1 mM。然后优化条件，以使用这些胶束增溶的底物来估计胰酯酶活性。在pH 8.5、2 - 4 mM油酸和15 - 30 mM牛磺胆酸钠的条件下可获得最大活性，以生育酚乙酸酯和胆固醇油酸酯作为底物时，检测的变异系数分别为7.4%和20.2%。胶束增溶的胆固醇油酸酯和生育酚乙酸酯，以及使用对硝基苯乙酸的非胶束系统，被用于估计人十二指肠抽吸物和大鼠胰腺匀浆中的酯酶活性。囊性纤维化患儿的酯酶活性大幅降低，且与胰蛋白酶和胰脂肪酶活性平行，这表明酯酶活性源自胰腺。因此，本研究结果为未来有关膳食酯水解和吸收的研究提供了基础。
