Claesson R, Karlsson M, Zhang Y, Carlsson J
Department of Oral Biology, Umeå University, Sweden.
J Leukoc Biol. 1996 Nov;60(5):598-602. doi: 10.1002/jlb.60.5.598.
The activation of collagenase released by polymorphonuclear leukocytes (PMNs) has been extensively studied in vitro, but the activation of the enzyme in vivo is not fully understood. For further evaluation of the relative role of oxidative and proteolytic mechanisms in the activation of collagenase, PMNs were stimulated by serum-opsonized zymosan under both aerobic and anaerobic conditions. The results showed that similar amounts of collagenase were released by the PMNs under aerobic and anaerobic conditions, but the activity of the released collagenase was twice as high under aerobic conditions as under anaerobic conditions. Under aerobic conditions the enzyme was rapidly activated by hypochlorous acid and chloramines, which are products of the myeloperoxidase-H2O2-chloride system of the PMNs. There was also a slow proteolytic activation of the enzyme, which could be ascribed to cathepsin G and possibly to some other serine proteases of PMNs. When extrapolating these findings to in vivo conditions, it seems probable that the oxidative activation of collagenase will proceed mainly by chloramines, which are more long-lived in the tissue than hypochlorous acid. In poorly oxygenated tissues, collagenase may be mainly activated by proteolytic mechanisms.
多形核白细胞（PMN）释放的胶原酶的激活在体外已得到广泛研究，但该酶在体内的激活情况尚未完全明了。为了进一步评估氧化和蛋白水解机制在胶原酶激活中的相对作用，在需氧和厌氧条件下，用血清调理的酵母聚糖刺激PMN。结果表明，在需氧和厌氧条件下，PMN释放的胶原酶量相似，但释放的胶原酶活性在需氧条件下是厌氧条件下的两倍。在需氧条件下，该酶被次氯酸和氯胺快速激活，次氯酸和氯胺是PMN的髓过氧化物酶-H2O2-氯化物系统的产物。该酶也存在缓慢的蛋白水解激活，这可归因于组织蛋白酶G，也可能归因于PMN的其他一些丝氨酸蛋白酶。当将这些发现外推至体内情况时，胶原酶的氧化激活似乎主要通过氯胺进行，氯胺在组织中的寿命比次氯酸更长。在低氧组织中，胶原酶可能主要通过蛋白水解机制激活。
