Structural analyses of a hereditary abnormal antithrombin III, antithrombin III Toyama, which has normal progressive antithrombin activity but no heparin cofactor activity, have been carried out to elucidate the molecular abnormality causing recurrent thrombophlebitis of a patient and to identify an amino acid residue essential for the binding with heparin. Abnormal antithrombin III was reduced, S-pyridylethylated, and treated with cyanogen bromide. Eleven fragments were isolated by the combination of Sephadex G-50 gel filtration and reversed-phase HPLC and compared with those from normal antithrombin III. One large fragment (CN-III) that appeared to have a different amino acid composition from that of the corresponding fragment from normal antithrombin mI was digested with trypsin, and the digests were separated by HPLC. The abnormal peptide was identified by comparing the peptide map with that from normal antithrombin Ill. Amino acid sequence analysis of the abnormal peptide indicated that the arginine-47 of normal antithrombin III had been replaced by cysteine in antithrombin HI Toyama. One base mutation, C --T, in the 5' terminal position of the arginine-47 genetic codon (CGT) is probably responsible for this substitution. These results also suggest that arginine-47 is an essential amino acid residue for the binding with heparin.Human antithrombin III is a single-chain a2-glycoprotein in plasma that is composed of 432 amino acid residues (1, 2). The glycoprotein forms a stoichiometric enzyme-inhibitor complex with a wide variety of serine proteases involved in the coagulation and the fibrinolysis systems and plays a principal role in regulation of the hemostatic mechanism (3, 4). The primary contact site (reactive site) of antithrombin III with proteases in the complex formation has been identified as Arg-Ser near the carboxyl terminus of the inhibitor (5, 6). Antithrombin III strongly binds heparin, which greatly accelerates the reaction rate of the inhibitor with proteases (3, 4). One tryptophan (4) and one or more lysine (7) residues (or both) of antithrombin III have been suggested to be involved in the binding with heparin, although their locations in the amino acid sequence have not been assigned.In 1965, Egeberg (8) described a thrombophilic family having a hereditary antithrombin III deficiency and, in 1974, Sas et al. (9) described a family with a thrombolism due to abnormal antithrombin III. Since then, several reports have been presented on the familial antithrombin III abnormality associated with thromboembolic disorder (10-15).Recently, we identified a Japanese family having the abnormal antithrombin III "antithrombin III Toyama" (16). The propositus of this family was a 23-year-old female suffering from recurrent thrombophlebitis. She was a homozyThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. gote transmitted from heterozygo...

Fibrin-related markers (FRMs), such as fibrin and fibrinogen degradation products (FDPs), D-dimer, and soluble fibrin (SF), are considered to be useful for the diagnosis of thrombosis. However, the evidence for the making of a diagnosis of thrombosis based on FRMs is, as yet, not fully established. Levels of FRMs are significantly elevated in patients with thrombosis, such as deep vein thrombosis, disseminated intravascular coagulation, and so on. In Japan, the D-dimer assay test result might be 2-fold higher than results for those assays commonly used in Europe and North America. The levels of SF are significantly elevated in patients before the onset of thrombosis, thus suggesting that the SF assay is useful not only for the diagnosis of thrombosis but also for diagnosing a prethrombotic state. Overall, elevated levels of FRMs indicate a high risk for thrombosis, and they are thus considered to be useful for the diagnosis of thrombosis.

Professor Eberhard F. Mammen greatly contributed to the understanding of the relationship between hemostatic abnormalities and liver diseases. The physiology of the hemostatic system is closely linked to liver function because the liver parenchymal cells produce most of the factors of the clotting and fibrinolytic systems. Acute or chronic hepatocellular diseases and hepatic failure including liver cirrhosis, vitamin K deficiency, liver surgery including liver transplantation, and sclerotherapy of bleeding esophageal varices, which were classified by Prof. Mammen, show various hemostatic abnormalities in the coagulation system, fibrinolytic system, platelets, and the reticuloendothelial system. Hemostatic abnormalities in patients with hepatic failure or in those that have undergone liver surgery are similar to those in disseminated intravascular coagulation. Prof. Mammen also contributed to the study of vitamin K-dependent clotting factors, antithrombin, and hemostatic molecular markers. Partly based on this work, the prothrombin time-international normalized ratio, several hemostatic molecular markers, and antithrombin therapy have been recently developed for the diagnosis and treatment of thrombosis.

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