Reis P, Holmberg K, Watzke H, Leser M E, Miller R
Nestlé Research Center, CH-1000 Lausanne 26, Switzerland.
Adv Colloid Interface Sci. 2009 Mar-Jun;147-148:237-50. doi: 10.1016/j.cis.2008.06.001. Epub 2008 Jul 3.
Lipases are acyl hydrolases that play a key role in fat digestion by cleaving long-chain triglycerides into polar lipids. Due to an opposite polarity between the enzyme (hydrophilic) and their substrates (lipophilic), lipase reaction occurs at the interface between the aqueous and the oil phases. Hence, interfaces are the key spots for lipase biocatalysis and an appropriate site for modulating lipolysis. Surprisingly enough, knowledge about the effects of the interfacial composition on lipase catalysis is still limited and only described by the term "interfacial quality". Recent systematic studies based on a biophysical approach allowed for the first time to show the effects of the interfacial microenvironment on lipase catalysis. These studies demonstrate that lipase activity as a function of interfacial composition is more attributed to substrate inaccessibility rather than to enzyme denaturation or inactivation, as it is often hypothesized. A detailed analysis of the interfacial properties of all compounds involved in triglyceride digestion revealed that lipolysis is a self-regulated reaction. This feedback mechanism can be explored as a new avenue to control lipase catalysis. To substantiate this hypothesis, oil hydrolysis in a model gastro-intestinal system was performed, which can be seen as an interfacial engineering approach to enzyme reactivity control. The presented characterization of the interfacial composition and its consequences provide a new approach for the understanding of lipase reactions at interfaces with direct impact on biotechnological and health care applications.
脂肪酶是一种酰基水解酶，通过将长链甘油三酯裂解为极性脂质，在脂肪消化过程中发挥关键作用。由于酶（亲水性）与其底物（亲脂性）之间存在相反的极性，脂肪酶反应发生在水相和油相的界面处。因此，界面是脂肪酶生物催化的关键部位，也是调节脂肪分解的合适位点。令人惊讶的是，关于界面组成对脂肪酶催化作用的影响的知识仍然有限，仅用“界面质量”这一术语来描述。最近基于生物物理方法的系统研究首次揭示了界面微环境对脂肪酶催化的影响。这些研究表明，脂肪酶活性作为界面组成的函数，更多地归因于底物难以接近，而不是如通常所假设的那样，归因于酶的变性或失活。对甘油三酯消化过程中所有相关化合物的界面性质进行详细分析后发现，脂肪分解是一种自我调节的反应。这种反馈机制可作为控制脂肪酶催化的新途径进行探索。为了证实这一假设，在模拟胃肠系统中进行了油脂水解实验，这可视为一种控制酶反应性的界面工程方法。所呈现的界面组成特征及其影响为理解界面处的脂肪酶反应提供了一种新方法，这对生物技术和医疗保健应用具有直接影响。
