Structure and function of platelet membrane glycoproteins-analysis of their mechanism using gene analysis and affinity labelling

1. 血小板膜糖蛋白Ib的多态性及其生理功能-糖钙素是GPIb的一种降解形式，经多种蛋白酶纯化并进一步降解。发现GPIb多态性来源于90kDa的糖肽部分。分析脑病患者GPIb多态性。虽然数量较少（n=18），但与日本正常受试者相比，C型GPIb较多，D型GPIb较少。血栓的发生与C型GPIb之间的关系需要通过更大的患者数量来证实。血小板糖蛋白的生物合成-巨核母细胞系表达GPIb、iib和IIIa抗原。GPIb和gpiib的前体存在于质膜分离的不同亚组分中。血栓性贫血伴前体型GPII b-我们发现2个不同家族的血栓性贫血患者GPII b异常且分子量较大。这种异常的GPII b被认为是上述GPII b的前体。分析这些患者的异常gpiib，将为我们了解gpiib和IIIa的生物合成机制提供有用的信息。

1. Polymorphism of platelet membrane glycoprotein Ib and its physiological function-Glycocalicin, a degraded form of GPIb,was purified and further degraded by various kinds of proteases. polymorphism of GPIb was found to be derived from glycopeptide portion of 90kDa. Polymorphysm of GPIb of patients with brain thombosis was analyzed. Although number is rather small(n=18), type C GPIb was found to be more and type D was found to be less in the patient than in the normal Japanese subjects. The relationship between the occurence of thrombosis and type C GPIb should be confirmed by using a larger number of patients.2. Biosynthesis of platelet glycoproteins-Megakaryoblast cell line was found to express GPIb,II b and IIIa antigens. Precursors of GPIb and GPII b were found in the different subfractions from plasma membrane fraction.3. Thrombasthenia with precursor type GPII b-We found 2 different families of patients with thrombasthenia who have an abnormal GPII b with larger molecular weight. This abnormal GPII b was identified as a precrsor of GPII b which was mentioned above. Analysis of the abnormal GPII b in these patients would give us useful infomation for understanding the mechanism of biosynthesis of GPII b and IIIa.