Studies on the physiological function of sugar chains and the activation mechanism of human von Willebrand factor

1. 新发现的一种蛋白质——双曲素的完整氨基酸序列。测定了异斑双耳蛇毒中血管性血友病因子（vWF）调节蛋白的含量。二硫联异二聚体是由α和β亚基组成的。这两个亚基都显示为c型凝集素基序，与另一种调节剂botrocetin只有45%的相似性。竞争研究表明，btiscetin结合在vWF的A1结构域的一个位点上，该位点靠近botrocetin结合位点。监测ABO血型错配骨髓移植患者血浆vWF中ABO血型抗原的表达。红细胞上的血型抗原逐渐转变为供者的血型，但vWF上的抗原即使在几年后仍保持着原始受体的血型。abo血型错配的外周血与脐带血干细胞移植结果相同。从Naja kaouthia眼镜蛇毒液中纯化出一种新的vwf结合和切割金属蛋白酶kaouthiagin。Kaouthiagin特异性地在Pro-708和Asp-709之间裂解vWF，降低vWF的多聚体结构，导致利斯托司汀诱导的血小板聚集性和vWF的胶原结合活性丧失。从A.blomhoffii蛇毒中纯化了一种新的血小板gpib结合蛋白mamushigin，并克隆了其cDNA。从黑蝮蛇蛇毒中纯化出一种新的纤维蛋白原裂解丝氨酸蛋白酶，并测定了该酶的完整氨基酸序列。Halystase还能裂解血浆激肽原，产生缓激肽，引起大鼠低血压。

1. The complete amino acid sequence of bitiscetin, a novel von. Willebrand factor (vWF) modulator protein from Bitis arietans snake venom, was determined. Bitiscetin was composed of disulfidelinked heterodimer of alpha and beta subunits. Both the subunits showed a C-type lectin motif and only 45% similarity to another modulator, botrocetin. The competition study suggests that bitiscetin binds to a site in the A1 domain of vWF located closely to the botrocetin-binding site.2. ABO blood group antigen expression on plasma vWF of the patients who received ABO-mismatched bone marrow transplantation was monitored. Blood group antigens on the red blood cells gradually turned to the donor's type, but the antigens on the vWF still maintained the original recipient's type even after several years. The same results were obtained in the case of ABO-mismatched peripheral blood and cord blood stem cell transplantation.3. A novel vWF-binding and -cleaving metalloproteinase named kaouthiagin was purified from Naja kaouthia cobra venom. Kaouthiagin specifically cleaved vWF between Pro-708 and Asp-709 to diminish the multimeric structure of vWF, resulting in the loss of ristocetin-induced platelet aggregability and collagen-binding activity of vWF.4. A novel platelet GPIb-binding protein named mamushigin was purified from A.blomhoffii snake venom and the cDNA of mamushigin was cloned.5. A novel fibrinogen-cleaving serine protease named halystase was purified from the snake venom of Agkistrodon halys blomhoffii and the complete amino acid sequence of halystase was determined. Halystase also cleaved plasma kininogen to produce bradykinin, causing the hypotension in rat.