Green B G, Weston H, Ashe B M, Doherty J, Finke P, Hagmann W, Lark M, Mao J, Maycock A, Moore V
Department of Enzymology, Merck Sharp and Dohme Research Laboratories, Rahway, New Jersey 07065.
Arch Biochem Biophys. 1991 Apr;286(1):284-92. doi: 10.1016/0003-9861(91)90042-h.
The human elastases isolated from polymorphonuclear neutrophils (PMN) and purulent sputum displayed identical kinetic constants toward substrates and inhibitors. The elastases from the two sources yield identical N-terminal sequences and were recognized by antiserum prepared against human sputum elastase (HSE) isozyme-4 (I-4). The data support the proposal put forth by Twumasi and Liener (1977, J. Biol. Chem. 252, 1917-1926) that the human elastase from sputum is of PMN origin. PMN elastases from other species displayed kinetic constants toward both substrates and inhibitors significantly different from the human enzyme. Therefore, extrapolation of inhibitor profiles from these elastases to the human source should be avoided. Four groups of isozymes were resolved from HSE by FPLC. Only the most basic isozyme (I-4) was obtained as a single species. The isozymes displayed identical macroscopic kinetic constants toward several substrates and two classes of inhibitors. The similar partition ratios observed with a cephalosporin-derived inhibitor suggest that the microscopic rate constants are also identical. The data support the proposal suggested by Baugh and Travis (1976, Biochemistry 15, 836-841) that HLE isozymes differ only in carbohydrate content. Whatever the source of human PMN elastase heterogeneity, it does not result in heterogeneous catalytic properties. In addition, a new protein was identified in elastase preparations derived from human sputum. This protein displayed homology to serine proteases and properties suggesting that it is identical to azurocidin.
从多形核中性粒细胞（PMN）和脓性痰中分离出的人弹性蛋白酶对底物和抑制剂表现出相同的动力学常数。来自这两种来源的弹性蛋白酶产生相同的N端序列，并被针对人痰弹性蛋白酶（HSE）同工酶-4（I-4）制备的抗血清识别。这些数据支持了Twumasi和Liener（1977年，《生物化学杂志》252卷，1917 - 1926页）提出的痰液中的人弹性蛋白酶起源于PMN的观点。来自其他物种的PMN弹性蛋白酶对底物和抑制剂的动力学常数与人类酶有显著差异。因此，应避免将这些弹性蛋白酶的抑制剂谱外推至人类来源。通过快速蛋白质液相色谱（FPLC）从HSE中分离出四组同工酶。只有最碱性的同工酶（I-4）以单一形式获得。这些同工酶对几种底物和两类抑制剂表现出相同的宏观动力学常数。用头孢菌素衍生抑制剂观察到的相似分配比表明微观速率常数也相同。这些数据支持了Baugh和Travis（1976年，《生物化学》15卷，836 - 841页）提出的人白细胞弹性蛋白酶（HLE）同工酶仅在碳水化合物含量上有所不同的观点。无论人PMN弹性蛋白酶异质性的来源如何，它都不会导致催化特性的异质性。此外，在源自人痰的弹性蛋白酶制剂中鉴定出一种新蛋白质。这种蛋白质与丝氨酸蛋白酶具有同源性，其特性表明它与天青杀素相同。
