Miyata T, Iwanaga S, Sakata Y, Aoki N, Takamatsu J, Kamiya T
J Biochem. 1984 Aug;96(2):277-87. doi: 10.1093/oxfordjournals.jbchem.a134836.
Previous studies in our laboratories (Miyata, T., et al. (1982) Proc. Natl. Acad. Sci. U.S. 79, 6132-6136) showed that the structural defect in a hereditarily abnormal plasminogen, plasminogen Tochigi, is due to replacement of Ala by Thr at position 600 from the NH2-terminal end. In the present studies, two abnormal plasminogens, plasminogens Tochigi II and Nagoya, obtained from other family members were analyzed to identify the structural impairment in these molecules. Amino acid sequence analysis of one of the tryptic peptides isolated, respectively, from plasminogens Tochigi II and Nagoya indicated that in both cases, Ala-600 (equivalent to Ala-55 of the chymotrypsin numbering system) had been replaced by Thr. No other substitutions at the active site and substrate-binding site residues, namely, His-57, Asp-102, Ser-195, and Asp-189, were found in the plasmin light chain variants, indicating that all these residues are intact. Moreover, the NH2-terminal heptapeptide sequences of the plasmin light chain variants isolated from plasminogens Tochigi II and Nagoya were identical to the sequence determined for the normal control. These results indicate that the absence of proteolytic activity of both abnormal molecules is due to the same amino acid substitution as that of previously reported plasminogen Tochigi.
我们实验室之前的研究（宫田，T.等人（1982年），《美国国家科学院院刊》79卷，6132 - 6136页）表明，遗传性异常纤溶酶原——富知纤溶酶原的结构缺陷是由于从NH2末端起第600位的丙氨酸被苏氨酸取代。在本研究中，对从其他家庭成员获得的两种异常纤溶酶原——富知II型纤溶酶原和名古屋纤溶酶原进行了分析，以确定这些分子中的结构损伤。分别从富知II型纤溶酶原和名古屋纤溶酶原中分离出的一种胰蛋白酶肽段的氨基酸序列分析表明，在这两种情况下，丙氨酸 - 600（相当于胰凝乳蛋白酶编号系统中的丙氨酸 - 55）都被苏氨酸取代。在纤溶酶轻链变体中，未在活性位点和底物结合位点残基（即组氨酸 - 57、天冬氨酸 - 102、丝氨酸 - 195和天冬氨酸 - 189）发现其他取代，这表明所有这些残基都是完整的。此外，从富知II型纤溶酶原和名古屋纤溶酶原中分离出的纤溶酶轻链变体的NH2末端七肽序列与正常对照所确定的序列相同。这些结果表明，这两种异常分子缺乏蛋白水解活性是由于与先前报道的富知纤溶酶原相同的氨基酸取代。
