ACTIVE SITE CHARACTERIZATION OF ACROSIN

顶体酶(E.N.3.4.21.10)是哺乳动物精子中一种独特的类胰酶 顶体，精子用来穿透卵子，这是 受精。这个项目的设计是为了继续描述 顶体酶，包括顶体酶的形态(结构)定义 顶体酶的活性部位，使特异性亲和标记(不可逆) 可以合成顶体酶抑制剂，它可以用来抑制 受精。将特别强调确定 顶体酶独特催化性质的作用机理 与顶体酶而不是胰酶(最常见的酶)特异结合的试剂 类似于顶体酶)。与顶体酶特异结合的药物将是 经修饰后成为亲和标记抑制剂。这些抑制剂将是 测试它们对顶体酶和功能性氨基酸的特异性 将确定参与结合的残基。自.以来 顶体酶是一种膜结合的蛋白水解酶，人工膜的形式 磷脂胶束(脂质体)将作为模型系统用于 研究膜结合顶体酶的各种参数对酶活性的影响。 抑制剂的设计。生物有效性(抑制 精子结合顶体酶)将被确定。最后，最重要的 对人类顶体酶和精子的实验将重复进行，以允许 准确评估这些药物可能的避孕效用 抑制剂。

Acrosin (E.N. 3.4.21.10) is a unique trypsin-like enzyme in mammalian sperm acrosomes and is used by sperm to penetrate the ovum, a prerequisite to fertilization. This project is designed to continue the characterization of acrosin, including the definition of the topography (structure) of acrosin's active site, so that specific affinity labeling (irreversible) acrosin inhibitors can be synthesized which may be used to inhibit fertilization. Particular emphasis will be placed on determining the mechanism of acrosin's unique catalytic properties in order to define reagents that specifically bind to acrosin and not trypsin (the enzyme most similar to acrosin). Agents that specifically bind to acrosin will be modified to become affinity labeling inhibitors. These inhibitors will be tested for their specificity to acrosin and the functional amino acid residues which participate in the binding will be determined. Since acrosin is a membrane bound proteinase, artifical membranes in the form of phospholipid micelles (liposomes) will be utilized as a model system to study various parameters of membrane bound acrosin which may affect the design of the inhibitors. The biological effectiveness (inhibition of sperm bound acrosin) will be ascertained. Finally, the most significant experiments will be repeated with human acrosin and sperm to permit an accurate evaluation of the possible contraceptive usefulness of these inhibitors.