EFFECT OF NEGATIVELY CHARGED ACTIVATING COMPOUNDS ON INACTIVATION OF FACTOR-XIIA BY CL INHIBITOR
EFFECT OF NEGATIVELY CHARGED ACTIVATING COMPOUNDS ON INACTIVATION OF FACTOR-XIIA BY CL INHIBITOR
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DOI：
10.1016/0003-9861(87)90606-0
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发表时间：
1987-08-01
影响因子：
3.9
通讯作者：
COLMAN, RW
中科院分区：
文献类型：
--
作者：
PIXLEY, RA;SCHMAIER, A;COLMAN, RW
人因子XII在暴露于带负电荷的表面如高岭土、硫苷脂和肝素时转化为酶形式，因子XIIa和因子XIIf。C.hivin.1抑制剂已被定量证明是因子XIIa和因子XIIf的主要血浆抑制剂。进行了研究，以确定是否存在的人工，带负电荷的表面影响的能力C.hivin.1抑制剂抑制因子XIIa和XIIf。高岭土和sulfatides减缓C.hivin.1抑制剂的抑制因子XIIa的速率。4.8和2倍，分别，而他们没有对C.hivin.1抑制剂的抑制因子XIIf的影响。肝素浓度为65 U/ml时，C.hivin.1抑制剂对因子XIIa的抑制率降低，但在相同浓度时，对C.hivin.1抑制剂抑制因子XIIf的能力影响较小。这些研究表明，带负电荷的表面保护因子XIIa，但不是因子XIIf从C.hivin.1抑制剂的抑制。由于因子XIIa和XIIf之间的差异在于因子XIIa中存在表面结合区，因此这种保护的基础必须存在于因子XII的表面结合残基中。这些在体外的事件表明，表面结合因子XIIa可以水解其生理底物，因子XI和前激肽释放酶，在一个环境中部分保护C.hivin.1抑制剂的抑制。
Human factor XII, upon exposure to negatively charged surfaces such as kaolin, sulfatides, and heparin, is converted to enzymatic forms, factor XIIa and factor XIIf. C.hivin.1 inhibitor has been quantitatively demonstrated to be the primary plasma inhibitor of both factor XIIa and factor XIIf. Studies were performed to determine whether the presence of artificial, negatively charged surfaces influenced the ability of C.hivin.1 inhibitor to inhibit factors XIIa and XIIf. Kaolin and sulfatides slowed the rate of inhibition of factor XIIa by C.hivin.1 inhibitor 4.8- and 2-fold, respectively, whereas they had no effect on the inhibition of factor XIIf by C.hivin.1 inhibitor. Heparin in a concentration of 65 U/ml decreased the inhibition rate of factor XIIa by C.hivin.1 inhibitor, but, at the same concentration, had less of an effect on the ability of C.hivin.1 inhibitor to inhibit factor XIIf. These studies indicate that negatively charged surfaces protect factor XIIa but not factor XIIf from inhibition from C.hivin.1 inhibitor. Since the difference between factors XIIa and XIIf consists of the presence of a surface binding region in factor XIIa, the basis of this protection must reside in the surface binding residues of factor XII. These in vitro events suggest that surface-bound factor XIIa may hydrolyze its physiologic substrates, factor XI and prekallikrein, in an environment partially protected from inhibition by C.hivin.1 inhibitor.