Kinetic properties of dromedary pancreatic lipase: A comparative study on emulsified and monomolecular substrate
Kinetic properties of dromedary pancreatic lipase: A comparative study on emulsified and monomolecular substrate
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DOI：
10.1016/j.colsurfb.2008.12.035
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发表时间：
2009-05-01
影响因子：
5.8
通讯作者：
Bezzine, Sofiane
中科院分区：
文献类型：
--
作者：
Jemel, Kram;Fendri, Ahmed;Bezzine, Sofiane
利用经典乳化体系和单分子膜技术，我们比较了单峰骆驼胰脂肪酶（DrPL）与哺乳动物（人）和鸟类（火鸡）模型的几种界面特性。与火鸡胰脂肪酶（TPL）不同，与人胰脂肪酶（HPL）不同的是，在没有胶原酶和胆盐的情况下，在低表面压力下，DrPL使用三丁酸甘油酯乳液或dicaprin单分子膜水解纯三丁酸甘油酯乳液，以及维持在低表面压力下的dicaprin膜。在没有任何添加剂的情况下，尽管在界面处积累了长链游离脂肪酸，DrPL也能够水解三油酸乳状液。两种哺乳动物胰脂肪酶（DrPL和HPL）的行为差异可以用每种酶的渗透能力来解释。DrPL的临界表面压力值（21 mN m(-1)）比HPL更重要。随后，单峰胰脂肪酶与界面有效地相互作用，并且在高界面能下不变性。利用含有单个可水解癸烷酯键的三种二卡布林异构体的光学纯立体异构体，在空气/水界面上作为单分子薄膜展开，对DrPL的表面压力依赖性、立体特异性和区域选择性进行了动力学研究。有趣的是，与所有先前研究的哺乳动物胰腺脂肪酶相比，在高表面压力下，DrPL对dicaprin异构体（1,2-sn-dicaprin和2,3-sn-dicaprin）的相邻酯基表现出最高的偏好。此外，DrPL形成一个胰脂肪酶亚群，当表面压力增加时，其立体偏好从sn-3位置切换到sn-1位置。(C) 2008 Elsevier B.V.版权所有
Using the classical emulsified system and the monomolecular film technique, we compared several interfacial properties of dromedary pancreatic lipase (DrPL) with those of a mammal (human) and an avian (turkey) model. Like turkey pancreatic lipase (TPL) and unlike human pancreatic lipase (HPL), in the absence of colipase and bile salts, using tributyrin emulsion or monomolecular films of dicaprin at low surface pressure, DrPL hydrolyses pure tributyrin emulsion, as well as dicaprin films maintained at low surface pressures. DrPL was also able to hydrolyse triolein emulsion in the absence of any additive and despite the accumulation of long-chain free fatty acids at the interface. The difference of behaviours between the two mammal pancreatic lipases (DrPL and HPL) can be explained by the penetration capacity of each enzyme. DrPL presents a critical Surface pressure value (21 mN m(-1)) that is more important than this of HPL. Subsequently, the dromedary pancreatic lipase interacts efficiently with interfaces and it is not denaturated at high interfacial energy.A kinetic study on the surface pressure dependency, stereospecificity and regioselectivity of DrPL was performed using optically pure stereoisomers of either three dicaprin isomers containing a single hydrolysable decanoyl ester bond that were spread as monomolecular films at the air/water interface. Interestingly, in comparison with all the previously studied mammal pancreatic lipases, DrPL presents the highest preference for adjacent ester groups of dicaprin isomers (1,2-sn-dicaprin and 2,3-sn-dicaprin) at high surface pressure. Furthermore, DrPL forms a pancreatic lipase subgroup in which the stereopreference switches from sn-3 position to the sn-1 position when increasing the surface pressure. (C) 2008 Elsevier B.V. All rights reserved.