skip to main content

SciTech ConnectSciTech Connect

Title: Hormonogenic donor Tyr2522 of bovine thyroglobulin. Insight into preferential T3 formation at thyroglobulin carboxyl terminus at low iodination level

Highlights: • A carboxy-terminal fragment (residues 2515–2750) was isolated from a low-iodine bTg. • Post-translational status of 8 tyrosines in bTg region 2515–2750 was assessed by MS. • Tyr2522 of bovine Tg is an interspecifically conserved hormonogenic donor site. • Propensities of Tyr residues to mono or diiodination optimize T3 yield from Tyr2748. - Abstract: A tryptic fragment (b5{sub TR,NR}), encompassing residues 2515–2750, was isolated from a low-iodine (0.26% by mass) bovine thyroglobulin, by limited proteolysis with trypsin and preparative, continuous-elution SDS–PAGE. The fragment was digested with Asp-N endoproteinase and analyzed by reverse-phase HPLC electrospray ionization quadrupole time-of-flight mass spectrometry, revealing the formation of: 3-monoiodotyrosine and dehydroalanine from Tyr2522; 3-monoiodotyrosine from Tyr2555 and Tyr2569; 3-monoiodotyrosine and 3,5-diiodotyrosine from Tyr2748. The data presented document, by direct mass spectrometric identifications, efficient iodophenoxyl ring transfer from monoiodinated hormonogenic donor Tyr2522 and efficient mono- and diiodination of hormonogenic acceptor Tyr2748, under conditions which permitted only limited iodination of Tyr2555 and Tyr2569, in low-iodine bovine thyroglobulin. The present study thereby provides: (1) a rationale for the preferential synthesis of T3 at the carboxy-terminal end of thyroglobulin, at low iodination level; (2) confirmation for the presence of an interspecifically conserved hormonogenic donor site in the carboxy-terminalmore » domain of thyroglobulin; (3) solution for a previous uncertainty, concerning the precise location of such donor site in bovine thyroglobulin.« less
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2] ;  [1]
  1. Dipartimento di Medicina e Scienze della Salute, Università del Molise, Via De Sanctis, snc, Campobasso 86100 (Italy)
  2. Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Via S. Pansini, 5, Napoli 80131 (Italy)
  3. Centro di Spettrometria di Massa Proteomica e Biomolecolare, ISA-CNR, Via Roma 52 a, Avellino 83100 (Italy)
  4. Dipartimento di Agraria, Università di Napoli “Federico II”, Parco Gussone, Portici (Napoli) 80055 (Italy)
Publication Date:
OSTI Identifier:
22416639
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 450; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CATTLE; CYSTEINE; DIIODOTYROSINE; DISSOCIATION; ELECTROPHORESIS; HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; HUMAN POPULATIONS; IODINATION; IODINE; ISOTHIOCYANATES; KETONES; MASS SPECTROSCOPY; MICE; PROTEOLYSIS; SYNTHESIS; THYROGLOBULIN; TIME-OF-FLIGHT METHOD; TRIIODOTHYRONINE; TRYPSIN; TYROSINE