STUDIES ON SOYBEAN TRYPSIN-INHIBITORS .8. DISULFIDE BRIDGES IN SOYBEAN BOWMAN-BIRK PROTEINASE INHIBITOR
STUDIES ON SOYBEAN TRYPSIN-INHIBITORS .8. DISULFIDE BRIDGES IN SOYBEAN BOWMAN-BIRK PROTEINASE INHIBITOR
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DOI：
10.1093/oxfordjournals.jbchem.a130295
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发表时间：
1973-01-01
影响因子：
2.7
通讯作者：
IKENAKA, T
中科院分区：
文献类型：
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作者：
ODANI, S;IKENAKA, T
大豆Bowman-Birk蛋白水解酶抑制剂在71个氨基酸组成的多肽链中含有14个半胱氨酸残基，胰酶抑制部位周围的5个半胱氨酸残基与胰凝乳蛋白酶抑制部位周围的半胱氨酸残基完全相同。为了确定二硫键的位置，用霉菌酸性蛋白酶、热裂解酶、链霉蛋白酶或枯草杆菌酶消化天然抑制物，得到适合于结构研究的胱氨酸肽。经Bio-Gel P-4柱层析和纸电泳法分离纯化。进一步用10N硫酸对含有α-半胱氨酸-半胱氨酸序列的多肽进行水解。氨基酸分析和相应的氨基酸末端分析表明，半胱氨酸多肽或其氧化衍生物在母体分子中有7个二硫键的位置，这表明存在两个同源的胰蛋白酶和胰凝乳蛋白酶抑制区，并且抑制物具有几乎对称的结构。
Soybean Bowman-Birk proteinase inhibitor contains 14 half-cystine residues in a relatively short polypeptide chain of 71 amino acid residues, and five half-cystine residues around the trypsin-inhibitory site are in absolutely identical locations to those around the chymotrypsin inhibitory site. To assign the locations of the disulfide bridges, the native inhibitor was digested with a mold acid proteinase, thermolysin, pronase or subtilisin to yield cystine peptides suitable for structural investigation. These were separated and purified by chromatography on a Bio-Gel P-4 column and by paper electrophoresis. A peptide containing a -Cys-Cys- sequence was further hydrolysed with 10 N sulfuric acid. Amino acid analyses and appropriate amino terminal analyses of the resulting cystine peptides or their oxidized derivatives revealed the positions of 7 disulfide bridges in the parent molecule, which indicated the presence of two homologous trypsin- and chymotrypsin-inhibitory regions, and an almost symmetrical structure of the inhibitor.