INTERFACIAL ACTIVATION OF SOLUBLE LIPOLYTIC ENZYMES

这项研究的目的是了解分子机制 水溶性脂解酶的界面活性。我们使用的是核磁共振， 结合动力学分析的QLS、SANS和荧光技术 研究磷脂与非特异性磷脂酶的相互作用 C(PLC)和磷脂酰肌醇特异性磷脂酶C(PI-PLC)形式 蜡状芽孢杆菌。考虑的一般关键问题包括以下内容。 (I)磷脂界面在不同的聚集体结构中如何变化， 这些变化是否与磷脂酶活性(即 我们能解释“界面活化”、“基质抑制”、“表面”吗？ 稀释度“等)？(Ii)磷脂酶C是什么物种？(Iii)可以统一 建立定量解释磷脂酶的动力学模型 以单体、胶束、洗涤剂混合胶束为底物的速率，以及 双层囊泡？ 这些研究的结果将使我们能够理解复杂的 两种细菌PLC型酶的界面行为。自.以来 细菌非特异性Plc具有至少与On相似的特征 中性哺乳动物PLC，我们为其开发的一般现象和原理 蜡状芽孢杆菌的酶可能外推到重要的哺乳动物 酵素。后者在细胞激活中发挥关键作用，包括 生产肌醇磷酸盐用于细胞内钙动员和 蛋白激酶C活化所需的二甘油三酯的生成。

The goal of this research is to understand the molecular mechanics of the interfacial activity of water-soluble lipolytic enzymes. We are using NMR, QLS, SANS, and fluorescence techniques in conjunction with kinetic analyses to investigate phospholipid interactions with the nonspecific phospholipase C (PLC) and the phosphatidylinositol-specific phospholipase C(PI-PLC) form Bacillus cereus. General key problems considered include the following. (i) How do phospholipid interfaces vary in different aggregate structures, and can these variations be correlated with phospholipase activity (i.e. can we explain "interfacial activation", "substrate inhibition", "surface dilution", etc.)? (ii) What phospholipase C species? (iii) Can a unified kinetic model be developed that quantitatively accounts for phospholipase rates toward substrate as monomer, micelles, detergent mixed micelles, and bilayer vesicles? The results of these studies will allow us to understand the complex interfacial behavior of two bacterial PLC type enzymes. Since the bacterial nonspecific Plc has characteristics similar to at least on neutral mammalian PLC, the general phenomena and rationale we develop for the B. cereus enzymes may be extrapolated to the important mammalian enzymes. The latter play key roles in cellular activation including the production of inositol phosphates for intracellular Ca2+ mobilization and the generation of diglyceride for activation of protein kinase C.