Relation between lipase structures and their catalytic ability to hydrolyse triglycerides and phospholipids
Relation between lipase structures and their catalytic ability to hydrolyse triglycerides and phospholipids
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DOI：
10.1016/j.enzmictec.2006.11.018
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发表时间：
2007-07-02
影响因子：
3.4
通讯作者：
Ferreira, Maria L.
中科院分区：
文献类型：
--
作者：
Gutierrez-Ayesta, Cecilia;Carelli, Amalia A.;Ferreira, Maria L.
研究了具有不同结构的脂肪酶在庚烷中于60 ℃在两相混合物heptare-buffer pH7.0中水解向日葵油、大豆卵磷脂及其混合物的催化能力。此外，分别以三亚油酸甘油酯和磷脂酰胆碱作为甘油三酯和磷脂的体系模型，采用Chem 3D 5.0 Ultra程序和MM 2（剑桥Soft）方法对底物吸附机理进行了理论研究。Lipolase 100 T，一种颗粒状二氧化硅固定化的Thermomorphin（以前为Humicola）羊毛脂酶的商业制剂，当测试向日葵油（85.3%转化为脂肪酸）及其与卵磷脂的混合物（100%转化为脂肪酸）时，证明了最高的脂肪酸转化率。来自Rhizomucor meihir（RML）的游离脂肪酶以卵磷脂为底物表现出最高的活性（35.6%转化为脂肪酸）。活性中心在表面的脂肪酶与底物的配位强度最高，空间位能降低。在RML和人工混合向日葵油-卵磷脂的情况下，MG、DG和FA之间的产物分配为：MG为29.70%，DG为32.96%，脂肪酸（FA）为37.34%。当使用Lipolase 100 T时，分布为：MG 14.91%、DG 15.46%和FA 69.63%。除了FA，甘油单酯（MG）和甘油二酯（DG）的一个新的产品时，卵磷脂存在（单独或混合），特别是当RML用作生物催化剂。使用Lipolase 100 T反应后未发现该峰的证据。这种新产物可能与卵磷脂中存在磷酸盐带电基团以及TG中FA的一个烃链裂解的可能性有关。一个可能的反应与暴露的活性中心的RML进行了讨论。这种新化合物的分配作为一个较短的脂肪酸链的MG-与9个碳原子-提出并支持进一步的分析分析。(c)2006年爱思唯尔公司All rights reserved.
Lipases with different structures were investigated for their catalytic ability to hydrolyse sunflower oil, soybean lecithin and their mixtures in heptane at 60 degrees C in a biphasic mixture heptare-buffer pH 7.0. Besides, the substrate adsorption mechanism was studied theoretically with the Chem 3D 5.0 Ultra program and the MM2 (Cambridge Soft) method by using trilinolein and phosphatidylcholine as system models of triglycerides and phospholipids, respectively. Lipolase 100T, a granulated silica immobilised commercial preparation of Thermomyces (formerly Humicola) lanuginosa lipase, evidenced the highest conversion to fatty acids when sunflower oil (85.3% conversion to fatty acids) and its mixture with lecithin (100 % conversion to fatty acids) were tested. The free lipase from Rhizomucor meiheir (RML) evidenced the highest activity with lecithin as substrate (35.6% conversion to fatty acids). The lipases with their active sites on the surface presented the highest strength of substrate coordination - as a decrease of steric energy. In the case of RML and the artificial mix sunflower oil-lecithin, the product distribution between MG, DG and FA was: 29.70% MG, 32.96% DG and 37.34% of fatty acids (FA). When Lipolase 100T was used, the distribution was: 14.91 % MG, 15.46% DG and 69.63% FA. Besides the FA, monoglycerides (MG) and diglycerides (DG) a new product was detected when lecithin was present (alone or in the mix) specially when RML was used as biocatalyst. No evidence of this peak was found after the reaction using Lipolase 100T. This new product can be related to the presence of phosphate charged group in lecithin and to the possibility of cracking of one of the hydrocarbon chains of the FA in TG. A possible reaction with the exposed active site of RML is discussed. The assignation of this new compound as a MG of a shorter fatty acid chain - with 9 carbon atoms - is presented and supported with further analytical analysis. (c) 2006 Elsevier Inc. All rights reserved.