Kinetics of the Factor XIa catalyzed activation of human blood coagulation Factor IX.
Kinetics of the Factor XIa catalyzed activation of human blood coagulation Factor IX.
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XIa 因子催化激活人凝血因子 IX 的动力学。
DOI：
10.1172/jci111343
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Tuszynski,GP
中科院分区：
文献类型：
--
作者：
Walsh,PN;Bradford,H;Sinha,D;Piperno,JR;Tuszynski,GP
为了研究人凝血因子XIA激活人凝血因子IX的动力学，用Zur和Nmerson(Zur，M.，and Y.Nmerson，1980，J.Biol)描述的牛凝血因子IX激活方法的改进，通过测量凝血因子IX释放三氯乙酸氚标记的激活肽来研究人凝血因子IX的激活动力学。化学，255：5703-5707)。人凝血因子XI与牛凝血因子XIIa孵育10-30min后，因子IX(88 NM)与CaCl2(5 MM)和纯(大于98%)凝血因子Xia(0.06-1.3 nM)孵育10-30min，三氯乙酸可溶的~3H-释放率呈线性关系。当~3H标记和未标记的凝血因子IX的摩尔分数和总凝血因子IX浓度保持不变时，~3H的释放先于凝血因子IXa的活性出现，~3H释放的百分比保持不变。用发色法和放射免疫法测定，当因子IX：因子Xia的摩尔比为70~5,600时，~3H释放的初始速率与因子Xia的浓度呈线性相关(r>0.98，P<0.001)。通过Lineweaver-Burk分析确定的动力学参数包括Km(0.49微米)，大约是血浆凝血因子IX浓度的五到六倍，因此可以调节反应。催化常数(Kcat)(7.7/S)约为Zur和Nmerson(Zur，M.和Y.Nmerson，1980，J.Biol)报道的值的20-50倍。化学，255：5703-5707)用于因子VIIa加组织因子激活因子IX。因此，根据体内产生的Xia和VIIa因子的相对数量以及其他可能影响反应速度的因素，这些动力学参数提供了评估内在和外部途径对IX因子激活的相对贡献所需的部分信息，并表明Xia因子催化的反应具有生理意义。
The kinetics of activation of human Factor IX by human Factor XIa was studied by measuring the release of a trichloroacetic acid-soluble tritium-labeled activation peptide from Factor IX by a modification of a method described for bovine Factor IX activation by Zur and Nemerson (Zur, M., and Y. Nemerson, 1980, J. Biol. Chem., 255:5703-5707). Initial rates of trichloroacetic acid-soluble 3H-release were linear over 10-30 min of incubation of Factor IX (88 nM) with CaCl2 (5 mM) and with pure (greater than 98%) Factor XIa (0.06-1.3 nM), which was prepared by incubating human Factor XI with bovine Factor XIIa. Release of 3H preceded the appearance of Factor IXa activity, and the percentage of 3H released remained constant when the mole fraction of 3H-labeled and unlabeled Factor IX was varied and the total Factor IX concentration remained constant. A linear correlation (r greater than 0.98, P less than 0.001) was observed between initial rates of 3H-release and the concentration of Factor XIa, measured by chromogenic assay and by radioimmunoassay and added at a Factor IX:Factor XIa molar ratio of 70-5,600. Kinetic parameters, determined by Lineweaver-Burk analysis, include Km (0.49 microM) of about five- to sixfold higher than the plasma Factor IX concentration, which could therefore regulate the reaction. The catalytic constant (kcat) (7.7/s) is approximately 20-50 times higher than that reported by Zur and Nemerson (Zur, M., and Y. Nemerson, 1980, J. Biol. Chem., 255:5703-5707) for Factor IX activation by Factor VIIa plus tissue factor. Therefore, depending on the relative amounts of Factor XIa and Factor VIIa generated in vivo and other factors which may influence reaction rates, these kinetic parameters provide part of the information required for assessing the relative contributions of the intrinsic and extrinsic pathways to Factor IX activation, and suggest that the Factor XIa catalyzed reaction is physiologically significant.Images
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血浆中人因子 XI 的酰胺分解测定：与凝血测定和新的快速放射免疫测定的比较。
影响因子：
20.3
作者：
Scott,CF;Sinha,D;Seaman,FS;Walsh,PN;Colman,RW
通讯作者：
Colman,RW
使用放射测定法对活化因子 IX 进行接触系统活化的量化。
影响因子：
20.3
作者：
R. Berkowitz;Y. Nemerson
通讯作者：
Y. Nemerson
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DOI：
10.1016/s0021-9258(19)62334-3
发表时间：
1978
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
P. Lindquist;K. Fujikawa;E. Davie
通讯作者：
E. Davie
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影响因子：
2.9
作者：
Miletich,JP;BrozeJr,GJ;Majerus,PW
通讯作者：
Majerus,PW
影响因子：
4.4
作者：
S. Kessler
通讯作者：
S. Kessler