CLEAVAGE OF BLOOD-COAGULATION FACTOR-XIII AND FIBRINOGEN BY THROMBIN DURING INVITRO CLOTTING
CLEAVAGE OF BLOOD-COAGULATION FACTOR-XIII AND FIBRINOGEN BY THROMBIN DURING INVITRO CLOTTING
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DOI：
10.1172/jci111849
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发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
SHUMAN, MA
中科院分区：
文献类型：
--
作者：
GREENBERG, CS;MIRAGLIA, CC;SHUMAN, MA
在体外凝血过程中研究凝血酶对凝血因子XIII （a2b2）和[人]纤维蛋白原的裂解，以确定这些事件的生理顺序。首先，测定富血小板血浆中纤维蛋白形成和因子XIII裂解的时间过程。使用纤维蛋白肽a的放射免疫测定法测定纤维蛋白原的裂解。在未还原的10%十二烷基硫酸钠-聚丙烯酰胺凝胶中，测定微量125I-Factor XIII的放射性碘化a链转化为凝血酶修饰的a链。在自发凝血过程中，125I-Factor XIII和纤维蛋白原在每个时间点的裂解率相似。24 .+-时，可见纤维蛋白单体的凝胶化。8%的纤维蛋白原断裂，21.1% +-。6%的因子XIII转化为因子XIII”。凝血酶裂解因子XIII转化为因子XIII”。在添加凝血酶的贫血小板血浆中，还研究了凝血酶对因子XIII和纤维蛋白原的裂解作用。为了测量XIIIa因子的活性，加入Gly-Pro-Arg-Pro后，纤维蛋白聚合被完全抑制。通过将[3H]腐胺掺入酪蛋白中来测定因子XIIIa的形成。切割50%纤维蛋白原和因子XIII所需添加凝血酶的浓度分别为0.65 U/ml和0.35 U/ml。凝血酶对纤维蛋白原的裂解率是因子XIII的43倍。用较低的Gly-Pro-Arg-Pro浓度来测定不完全抑制纤维蛋白聚合对XIII因子和纤维蛋白原裂解的影响。凝血酶的切割因子XIII而非纤维蛋白原依赖于纤维蛋白聚合的程度。纤维蛋白聚合抑制程度越显著，因子XIIIa的形成速度越慢。在富血小板血浆中，凝血酶裂解因子XIII和纤维蛋白原是自发凝血过程中密切相关的事件。凝血过程中，纤维蛋白聚合可增强凝血过程中因子XIII的裂解。
Thrombin cleavage of blood coagulation Factor XIII (a2b2) and [human] fibrinogen was studied during in vitro clotting to determine the physiologic sequence of these events. First, the time course of fibrin formation and cleavage of Factor XIII was measured in platelet-rich plasma. Cleavage of fibrinogen was measured by using a radioimmunoassay for fibrinopeptide A. Conversion of trace amounts of radioiodinated a-chains of 125I-Factor XIII to thrombin-modified a-chains was measured in unreduced 10% sodium dodecyl sulfate-polyacrylamide gels. During spontaneous clotting, a similar percentage of 125I-Factor XIII and fibrinogen was cleaved at each time point. Visible gelation of polymerized fibrin monomer occurred when 24 .+-. 8% of fibrinogen was cleaved and 21 .+-. 6% of Factor XIII was converted to Factor XIII''. Thrombin cleavage of Factor XIII was converted to Factor XIII''. Thrombin cleavage of Factor XIII and fibrinogens was also studied in platelet-poor plasma to which thrombin was added. In order to measure Factor XIIIa activity, fibrin polymerization was completely inhibited by the addition of Gly-Pro-Arg-Pro. Factor XIIIa formation was measured by the incorporation of [3H]putrescine into casein. The concentration of added thrombin required to cleave 50% of fibrinogen and Factor XIII was 0.65 U/ml and 0.35 U/ml, respectively. The rate of cleavage of fibrinogen by thrombin was 43-fold greater than cleavage of Factor XIII. Lower Gly-Pro-Arg-Pro concentration were used to determine the effects of incompletely inhibiting fibrin polymerization on cleavage of Factor XIII and fibrinogen. Thrombin cleavage of Factor XIII but not fibrinogen was dependent on the extent of fibrin polymerization. The more marked the degree of inhibition of fibrin polymerization, the slower the rate of Factor XIIIa formation. In platelet-rich plasma, thrombin cleavage of Factor XIII and fibrinogen are closely related events during spontaneous clotting. Cleavage of Factor XIII during clotting is enhanced by fibrin polymerization in platelet-poor plasma.