Patterson B C, Sang Q A
Department of Chemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
J Biol Chem. 1997 Nov 14;272(46):28823-5. doi: 10.1074/jbc.272.46.28823.
Angiostatin is one of the most potent inhibitors of angiogenesis. Reports have shown that metalloelastase, pancreas elastase, plasmin reductase, and plasmin convert plasminogen to angiostatin. However, the cleavage sites of plasminogen by those enzymes have not been determined. Here we demonstrate that two members of the human matrix metalloproteinase (MMP) family, matrilysin (MMP-7) and gelatinase B/type IV collagenase (MMP-9), hydrolyze human plasminogen to generate angiostatin fragments. The cleavage sites have been determined. The 58-kDa bands derived from plasminogen by MMP-7 and MMP-9 both have the N-terminal sequence KVYLSEXKTG, which corresponds to that of angiostatin. This N terminus is identical to that of the starting plasminogen itself and corresponds to residues 97-106 of prepro-plasminogen. The 42- and 38-kDa bands generated by MMP-7 both have the N-terminal sequence VVLLPNVETP, which corresponds to the amino acid sequence 467-476 of prepro-plasminogen, between kringle domain 4 and 5. MMP-9 cleaves plasminogen to generate a 42-kDa fragment with the N-terminal sequence PVVLLPNVE, 1 residue upstream of the MMP-7 cleavage site. These results indicate that MMP-7 and MMP-9 may regulate new blood vessel formation by cleaving plasminogen and generating angiostatin molecules.
血管抑素是最有效的血管生成抑制剂之一。报告显示，金属弹性蛋白酶、胰腺弹性蛋白酶、纤溶酶还原酶和纤溶酶可将纤溶酶原转化为血管抑素。然而，这些酶对纤溶酶原的切割位点尚未确定。在此，我们证明人类基质金属蛋白酶（MMP）家族的两个成员，基质溶素（MMP-7）和明胶酶B/IV型胶原酶（MMP-9），可水解人类纤溶酶原以产生血管抑素片段。切割位点已确定。由MMP-7和MMP-9作用于纤溶酶原产生的58 kDa条带均具有N端序列KVYLSEXKTG，该序列与血管抑素的N端序列一致。这个N端与起始纤溶酶原本身的N端相同，对应于前纤溶酶原的97-106位残基。由MMP-7产生的42 kDa和38 kDa条带均具有N端序列VVLLPNVETP，该序列对应于前纤溶酶原467-476位氨基酸序列，位于kringle结构域4和5之间。MMP-9切割纤溶酶原产生一个42 kDa片段，其N端序列为PVVLLPNVE，位于MMP-7切割位点上游1个残基处。这些结果表明，MMP-7和MMP-9可能通过切割纤溶酶原并生成血管抑素分子来调节新血管的形成。
