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Structure‐function relationship in thyroglobulin: amino acid sequence of two different thyroxine‐containing peptides from porcine thyroglobulin.
Author(s) -
Marriq C.,
Rolland M.,
Lissitzky S.
Publication year - 1982
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1982.tb01181.x
Subject(s) - cyanogen bromide , thyroglobulin , edman degradation , peptide sequence , peptide , trypsin , biology , tyrosine , biochemistry , amino acid , size exclusion chromatography , ion chromatography , chemistry , thyroid , enzyme , endocrinology , gene
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.