Matsushita M, Thiel S, Jensenius J C, Terai I, Fujita T
Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima, Japan.
J Immunol. 2000 Sep 1;165(5):2637-42. doi: 10.4049/jimmunol.165.5.2637.
Mannose (or mannan)-binding lectin (MBL) is an oligomeric serum lectin that plays a role in innate immunity by activating the complement system. In human, two types of MBL-associated serine protease (MASP-1 and MASP-2) and a truncated protein of MASP-2 (small MBL-associated protein; sMAP or MAp19) are complexed with MBL. To clarify the proteolytic activities of MASP-1 and MASP-2 against C4, C2, and C3, we isolated these two types of MASP in activated forms from human serum by sequential affinity chromatography. On an anti-MASP-1 column, MASP-2 passed through the column in the presence of EDTA and high salt concentration, whereas MASP-1 was retained. Isolated MASP-1 and MASP-2 exhibited proteolytic activities against C3 and C4, respectively. C2 was activated by both MASPs. C1 inhibitor (C1 INH), an inhibitor for C1r and C1s, formed equimolar complexes with MASP-1 and MASP-2 and inhibited their proteolytic activities.
甘露糖（或甘露聚糖）结合凝集素（MBL）是一种寡聚血清凝集素，通过激活补体系统在固有免疫中发挥作用。在人类中，两种类型的MBL相关丝氨酸蛋白酶（MASP-1和MASP-2）以及MASP-2的截短蛋白（小MBL相关蛋白；sMAP或MAp19）与MBL复合。为了阐明MASP-1和MASP-2对C4、C2和C3的蛋白水解活性，我们通过连续亲和层析从人血清中分离出这两种活化形式的MASP。在抗MASP-1柱上，在EDTA和高盐浓度存在的情况下，MASP-2通过柱子，而MASP-1被保留。分离出的MASP-1和MASP-2分别表现出对C3和C4的蛋白水解活性。C2被两种MASP激活。C1抑制剂（C1 INH），一种C1r和C1s的抑制剂，与MASP-1和MASP-2形成等摩尔复合物并抑制它们的蛋白水解活性。
