title: The isolation of identical thyroxine containing amino acid sequences from bovine, ovine and porcine thyroglobulins.
abstract: Identical, thyroxine containing tryptic peptides have been isolated from digests of bovine, ovine and procine thyroglobulins. This 19 residue hormone containing sequence, NH2-Asn-Ile-Phe-Glu-T4-Gln-Val-Asp-Ala-Gln-Pro-Leu-Arg-Pro-Cys-Glu-Leu-G in-Arg- COOH, is completely conserved across these three species, and it represents a principal site of thyroxine synthesis. HPLC maps of tryptic digests of the thyroglobulins have been monitored at several wavelengths and suggest that, in each case, only a small number of tryptic peptides are iodinated in vivo and that an even smaller number of tryptic peptides contain thyroid hormone. These data are consistent with a high degree of selectivity in iodination of tyrosines within thyroglobulin and the subsequent coupling of these selected tyrosines to form thyroid hormone.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D010446:Peptide Fragments / Q000032:analysis*; D012756:Sheep; D013045:Species Specificity; D013552:Swine; D013954:Thyroglobulin; D013974:Thyroxine / Q000032:analysis*; D014357:Trypsin
chemical_list: D010446:Peptide Fragments; D013954:Thyroglobulin; D014357:Trypsin; D013974:Thyroxine