Enzyme‐catalyzed hydrolysis of 18‐methyl eicosanoic acid‐cysteine thioester
Enzyme‐catalyzed hydrolysis of 18‐methyl eicosanoic acid‐cysteine thioester
复制标题
酶催化水解18-甲基二十烷酸-半胱氨酸硫酯
DOI：
10.1002/ejlt.200300800
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
U. Bornscheuer
中科院分区：
文献类型：
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作者：
Franka Ganske;H. Meyer;H. Deutz;U. Bornscheuer
18-甲基二十烷酸（18-MEA）是人类和动物头发表面角质层内通过半胱氨酸硫酯键连接的主要脂肪酸成分。过量的18-MEA导致脂肪毛发，并且使用一系列市售水解酶研究了用于酶促去除的温和方法。纯的18-MEA只能以μg的量从天然来源获得，因此它是在7步化学合成中以克的量合成的，总产率为34%。以18-MEA为起始原料，以85%的产率得到相应的半胱氨酸硫酯（Cys-18-MEA）作为模型化合物。使用Ellmanns试剂检测作用于Cys-18-MEA的水解酶，然后在410 nm处对5-硫代-2-硝基苯甲酸进行分光光度定量。这导致鉴定出6种酶，其中来自洋葱假单胞菌（Amano PS）的脂肪酶是最具活性的酶。使用Amano PS，在30 °C下在5小时反应时间内实现了60%的Cys-18-MEA转化率。还使用人发样品进行了初步结果，结果表明，在将头发与Amano PS孵育后，可检测到水解活性。
18-Methyleicosanoic acid (18-MEA) is the major fatty acid component linked by a cysteine thioester bond within the cuticle at the surface of hair of humans and animals. An excess of 18-MEA results in fatty hair and a mild method for enzymatic removal was investigated using a range of commercially available hydrolases. Pure 18-MEA is available from natural sources only in μg quantities, so it was synthesized in gram-amounts in a 7-step chemical synthesis at an overall yield of 34%. Starting from 18-MEA the corresponding thioester with cysteine (Cys-18-MEA) serving as model compound was obtained at a yield of 85%. The detection of hydrolases acting on Cys-18-MEA was performed using Ellmanns reagent followed by spectrophotometric quantification of 5-thio-2-nitrobenzoic acid at 410 nm. This led to the identification of 6 enzymes with lipase from Pseudomonas cepacia (Amano PS) as the most active one. With Amano PS, 60% conversion of Cys-18-MEA was achieved within 5 h-reaction time at 30 °C. Preliminary results using samples of human hair were also performed and showed that hydrolytic activity is detectable after incubation of the hair with Amano PS.