Terai I, Kobayashi K, Matsushita M, Fujita T, Matsuno K
Department of Laboratory Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Int Immunol. 1995 Oct;7(10):1579-84. doi: 10.1093/intimm/7.10.1579.
We determined the presence in human serum of a complex consisting of mannose-binding protein (MBP), MBP-associated serine protease (MASP), which is a C1s-like protein with complement activation activity, and alpha 2-macroglobulin (alpha 2M). Binding between these three molecules was in an ascending order of MBP, MASP and alpha 2M, in that alpha 2M bound directly to MASP, possibly through covalent bonds, whereas the binding between MBP and MASP was reversible and Ca(2+)-dependent. Since it was found that alpha 2M can inhibit complement activation by MASP and that MASP in the complex lacks esterolytic activity, it is conceivable that alpha 2M plays a regulatory role in MBP-derived complement activation via a mechanism involving MASP (the lectin pathway).
我们确定了在人血清中存在一种复合物，该复合物由甘露糖结合蛋白（MBP）、MBP 相关丝氨酸蛋白酶（MASP，一种具有补体激活活性的 C1s 样蛋白）和α2-巨球蛋白（α2M）组成。这三种分子之间的结合顺序为 MBP、MASP 和α2M，即α2M 直接与 MASP 结合，可能通过共价键，而 MBP 和 MASP 之间的结合是可逆的且依赖于 Ca(2+)。由于发现α2M 可抑制 MASP 的补体激活，且复合物中的 MASP 缺乏酯酶活性，因此可以推测α2M 通过涉及 MASP 的机制（凝集素途径）在源自 MBP 的补体激活中发挥调节作用。
