Marriq C, Rolland M, Lissitzky S
EMBO J. 1982;1(4):397-401. doi: 10.1002/j.1460-2075.1982.tb01181.x.
From the cyanogen bromide (CNBr) treatment of porcine thyroglobulin a peptide of mol. wt. 15 000, CNBr-b1, was purified by gel filtration and ion-exchange chromatography. CNBr-b1 contained 50% of the thyroxine (T4) content of the protein. After digestion with trypsin and protease from Staphylococcus aureus V-8, thyroxine-containing peptides were purified and analyzed by microsequence analysis using the colored Edman's reagent dimethylaminoazobenzeneisothiocyanate . Two different sequences harboring T4 were identified: sequence 1, His-Asp-Asp-Asp-T4-Ala-Thr-(Glx,Gly)-Leu-Tyr-Phe-Ser-Ser-Arg, which contains 1 mol T4/mol peptide and sequence 2, Asp-(Tyr/MIT/DIT/T4)-Phe-Ile-Leu-X-Pro-Val-, which is a mixture of the same peptide at different levels of iodination and coupling. These sequences are likely to be representative of distinct hormonogenic sites, the former giving evidence of early iodinated tyrosine residues where preferential coupling into hormonal residues occurs especially at low iodine levels and the latter representing less reactive site(s) operative at higher iodine levels.
通过对猪甲状腺球蛋白进行溴化氰（CNBr）处理，得到了分子量为15000的肽段CNBr-b1，该肽段通过凝胶过滤和离子交换色谱法进行了纯化。CNBr-b1含有该蛋白质50%的甲状腺素（T4）含量。在用来自金黄色葡萄球菌V-8的胰蛋白酶和蛋白酶消化后，对含甲状腺素的肽段进行了纯化，并使用有色的埃德曼试剂二甲基氨基偶氮苯异硫氰酸酯通过微序列分析进行了分析。鉴定出了两个含有T4的不同序列：序列1，His-Asp-Asp-Asp-T4-Ala-Thr-(Glx,Gly)-Leu-Tyr-Phe-Ser-Ser-Arg，其每摩尔肽含有1摩尔T4；序列2，Asp-(Tyr/MIT/DIT/T4)-Phe-Ile-Leu-X-Pro-Val-，这是同一肽段在不同碘化和偶联水平下的混合物。这些序列可能代表不同的激素生成位点，前者表明早期碘化的酪氨酸残基，在低碘水平时尤其优先偶联形成激素残基，而后者代表在高碘水平下起作用的反应性较低的位点。
