Ransac S, Gargouri Y, Moreau H, Verger R
Centre de Biochimie et de Biologie Moléculaire, Centre National de Recherche Scientifique, Marseille, France.
Eur J Biochem. 1991 Dec 5;202(2):395-400. doi: 10.1111/j.1432-1033.1991.tb16387.x.
We studied the covalent inhibition of lipases by the monolayer technique. We report the inactivation of porcine pancreatic and human and rabbit gastric lipases, acting on mixed monomolecular films of dicaprin containing tetrahydrolipstatin or new hydrophobic disulfide compounds, which can be described as a 'poisoned-interface' system. A kinetic model is presented for depicting the covalent inactivation of lipolytic enzymes at a lipid/water interface. The stoichiometry of the interfacial situation can be described as follows: one lipase molecule embedded among 10(5) substrate molecules will be inactivated to half its initial velocity by the presence of 10 tetrahydrolipstatin molecules. This inactivation was independent of the surface pressure. When tested in the form of mixed films, all the disulfide compounds investigated specifically reduced the hydrolysis of 1,2-didecanoyl-sn-glycerol films by gastric lipases, but did not affect hydrolysis by pancreatic lipase. With this poisoned-interface system, tetrahydrolipstatin was found to be the most potent inactivator, whereas disulfide compounds showed a higher degree of selectivity than tetrahydrolipstatin.
我们采用单分子层技术研究了脂肪酶的共价抑制作用。我们报道了猪胰脂肪酶、人胃脂肪酶和兔胃脂肪酶在含有四氢脂抑素或新型疏水二硫化合物的二癸酸混合单分子膜作用下的失活情况，这可被描述为一种“中毒界面”系统。提出了一个动力学模型来描述脂解酶在脂质/水界面的共价失活。界面情况的化学计量关系如下：在10⁵个底物分子中嵌入的一个脂肪酶分子，会因10个四氢脂抑素分子的存在而失活至其初始速度的一半。这种失活与表面压力无关。当以混合膜的形式进行测试时，所有研究的二硫化合物都能特异性降低胃脂肪酶对1,2 - 二癸酰 - sn - 甘油膜的水解作用，但不影响胰脂肪酶的水解作用。在这个中毒界面系统中，发现四氢脂抑素是最有效的失活剂，而二硫化合物表现出比四氢脂抑素更高的选择性。
