Verger R, Rietsch J, Van Dam-Mieras M C, de Haas G H
J Biol Chem. 1976 May 25;251(10):3128-33.
The kinetic aspects of lipolysis by pancreatic lipase and phospholipase A2 from different sources have been compared using monomolecular films of short chain lipids as the substrates. Phosphatidylcholine monolayers, in contrast to phosphatidylethanolamine and phosphatidylglycerol monolayers, were resistant to hydrolysis by pancreatic lipase. The induction time, measured during pre-steady state conditions, increased abruptly for a given value of the surface pressure. This appears to be due to a degree of lipid packing above which the enzyme no longer can penetrate the lipid film. The existence of an optimum in the velocity versus surface pressure profile is the result of at least two counterbalancing factors. As the surface pressure increases, the amount of enzyme present in the interface decreases, whereas the minimal specific activity of the enzyme increases. From this study with monolayers we can conclude that activity of lipolytic enzymes used as tools for probing biological membranes will be greatly influenced by the physiochemical nature of the membrane-water interface. Thus, studies such as this one which can measure the penetrating ability of various lipolytic enzymes can be useful in deriving a better understanding of biological membrane structure.
利用短链脂质的单分子膜作为底物，比较了不同来源的胰腺脂肪酶和磷脂酶A2的脂解动力学方面。与磷脂酰乙醇胺和磷脂酰甘油单分子层相比，磷脂酰胆碱单分子层对胰腺脂肪酶的水解具有抗性。在预稳态条件下测量的诱导时间，对于给定的表面压力值会突然增加。这似乎是由于一定程度的脂质堆积，超过此程度酶就无法再穿透脂质膜。速度与表面压力曲线中存在最佳值是至少两个相互平衡因素的结果。随着表面压力增加，界面中存在的酶量减少，而酶的最小比活性增加。从这项关于单分子层的研究中我们可以得出结论，用作探测生物膜工具的脂解酶的活性将受到膜 - 水界面的物理化学性质的极大影响。因此，像这样能够测量各种脂解酶穿透能力的研究，有助于更好地理解生物膜结构。
