Winberg J O, Kolset S O, Berg E, Uhlin-Hansen L
Department of Biochemistry Institute of Medical Biology, University of Tromso, Tromso, Norway.
J Mol Biol. 2000 Dec 8;304(4):669-80. doi: 10.1006/jmbi.2000.4235.
Matrix metalloproteinases (MMPs) secreted from the leukemic macrophage cell-line THP-1 have been investigated. Under serum-free conditions, this cell-line synthesizes and secretes proMMP-9, which was detected in the culture medium as a monomer of 92 kDa, and in dimeric forms, including a homodimer of approximately 225 kDa. In addition, a new heterodimer complex is described, in which proMMP-9 is covalently linked to the core protein of chondroitin sulphate proteoglycan (CSPG) through one or more disulphide bridges. After SDS-PAGE electrophoresis, at least two forms of this complex were detected, a large form in the stacking gel and a smaller form with an estimated size of 300 kDa. When the CS chains were removed by chondroitin ABC lyase treatment, heterodimers of proMMP-9/CSPG core protein of approximately 145, 127 and 109 kDa were found, based on zymography and Western blots. Since as much as 10-15 % of the total proMMP-9 secreted from THP-1 cells was covalently linked to CSPG, this association may have important implications for transport, targetting and regulation of the enzyme activity.
对白血病巨噬细胞系THP-1分泌的基质金属蛋白酶（MMPs）进行了研究。在无血清条件下，该细胞系合成并分泌前MMP-9，其在培养基中以92 kDa的单体形式以及二聚体形式（包括约225 kDa的同型二聚体）被检测到。此外，还描述了一种新的异源二聚体复合物，其中前MMP-9通过一个或多个二硫键与硫酸软骨素蛋白聚糖（CSPG）的核心蛋白共价连接。在SDS-PAGE电泳后，检测到该复合物的至少两种形式，一种在堆积胶中的大形式和一种估计大小为300 kDa的较小形式。当通过软骨素ABC裂解酶处理去除CS链时，基于酶谱分析和蛋白质免疫印迹法发现了约145、127和109 kDa的前MMP-9/CSPG核心蛋白异源二聚体。由于从THP-1细胞分泌的总前MMP-9中多达10 - 15%与CSPG共价连接，这种关联可能对该酶的运输、靶向作用和酶活性调节具有重要意义。
