Young J D, Leong L G, Liu C C, Damiano A, Wall D A, Cohn Z A
Cell. 1986 Oct 24;47(2):183-94. doi: 10.1016/0092-8674(86)90441-1.
Cytotoxic T lymphocytes and lymphocytes with NK-like activity contain a serine esterase activity which has been localized to their cytoplasmic granules by cytochemistry and subcellular fractionation studies. The serine esterase-specific inhibitor 3H-DFP labels two protein species in the granules. The two proteins, referred to as serine esterases 1 and 2 (SE 1 and SE 2), migrate with Mr of 34-36 kd and 28-30 kd, respectively, under reducing conditions. SE 1 shows trypsin-like activity and has been purified to apparent homogeneity. Under nonreducing conditions, SE 1 has an Mr of 60-66 kd, suggesting that it may consist of two disulfide-linked subunits of 34-36 kd each. SE 1 cleaves fibrin and casein, has a pl greater than 10, and optimal activity at pH 8. The substrate specificity of SE 2 is not known. The serine esterase activity is secreted by lymphocytes that have been stimulated with the calcium ionophore A23187. The serine esterases described here could play an active role in cell-mediated killing.
细胞毒性T淋巴细胞和具有自然杀伤细胞样活性的淋巴细胞含有一种丝氨酸酯酶活性，通过细胞化学和亚细胞分级分离研究已将其定位到它们的细胞质颗粒中。丝氨酸酯酶特异性抑制剂3H-DFP标记颗粒中的两种蛋白质。这两种蛋白质，分别称为丝氨酸酯酶1和2（SE 1和SE 2），在还原条件下迁移时的相对分子质量分别为34 - 36kd和28 - 30kd。SE 1显示出胰蛋白酶样活性，并且已被纯化至表观均一性。在非还原条件下，SE 1的相对分子质量为60 - 66kd，表明它可能由两个各自为34 - 36kd的二硫键连接的亚基组成。SE 1可切割纤维蛋白和酪蛋白，其等电点大于10，在pH 8时具有最佳活性。SE 2的底物特异性尚不清楚。丝氨酸酯酶活性由用钙离子载体A23187刺激的淋巴细胞分泌。这里描述的丝氨酸酯酶可能在细胞介导的杀伤中发挥积极作用。
