Krust B, Galabru J, Hovanessian A G
Biochem Biophys Res Commun. 1983 Nov 30;117(1):350-7. doi: 10.1016/0006-291x(83)91583-8.
Treatment of patients with interferon or inducers of interferon results in an enhanced level of a protein kinase activity found in platelets (1,3). The kinase activity is responsible for the phosphorylation of a 70-72,000 molecular weight protein (72K protein) found in blood plasma. By the means of a technique based on the precipitation of this protein kinase system (the protein kinase and its substrate), we show here that the 72K protein is the alpha-chain of fibrinogen. During the coagulation process induced by thrombin, the 32P-labelled 72K protein is recovered in the clot. After incubation in the presence of thrombin, the 72K protein looses a small polypeptide of 2-3000 in molecular weight resulting a shift in its isoelectric point (pI) from 6.8-7.0 to 7.5. At the end of the coagulation process, the 32P-labelled 72K protein becomes undetectable since it gives rise to a covalently linked alpha-polymer of a high molecular weight. In accord with these results, the 72K protein could be precipitated by antibodies against human fibrinogen.
用干扰素或干扰素诱导剂治疗患者会导致血小板中发现的蛋白激酶活性水平升高（1,3）。该激酶活性负责血浆中一种分子量为70 - 72,000的蛋白质（72K蛋白）的磷酸化。通过基于该蛋白激酶系统（蛋白激酶及其底物）沉淀的技术，我们在此表明72K蛋白是纤维蛋白原的α链。在凝血酶诱导的凝血过程中，32P标记的72K蛋白在凝块中被回收。在凝血酶存在下孵育后，72K蛋白失去了一个分子量为2 - 3000的小多肽，导致其等电点（pI）从6.8 - 7.0变为7.5。在凝血过程结束时，32P标记的72K蛋白变得无法检测到，因为它产生了一种高分子量的共价连接的α聚合物。与这些结果一致，72K蛋白可被抗人纤维蛋白原抗体沉淀。
