title: Hormonogenic donor Tyr2522 of bovine thyroglobulin. Insight into preferential T3 formation at thyroglobulin carboxyl terminus at low iodination level.
abstract: A tryptic fragment (b5TR,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-terminal domain of thyroglobulin; (3) solution for a previous uncertainty, concerning the precise location of such donor site in bovine thyroglobulin.
authors.affiliation: Dipartimento di Medicina e Scienze della Salute, Università del Molise, Via De Sanctis, snc, Campobasso 86100, Italy. Electronic address: giovanni.cetrangolo@unimol.it.
authors.forename: Giovanni Paolo
authors.initials: GP
authors.lastname: Cetrangolo
authors.affiliation: Dipartimento di Medicina e Scienze della Salute, Università del Molise, Via De Sanctis, snc, Campobasso 86100, Italy. Electronic address: alessia.arcaro@unimol.it.
authors.forename: Alessia
authors.initials: A
authors.lastname: Arcaro
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Via S. Pansini, 5, Napoli 80131, Italy. Electronic address: alessiolepore@alice.it.
authors.forename: Alessio
authors.initials: A
authors.lastname: Lepore
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Via S. Pansini, 5, Napoli 80131, Italy. Electronic address: mariagraf@tiscali.it.
authors.forename: Maria
authors.initials: M
authors.lastname: Graf
authors.affiliation: Centro di Spettrometria di Massa Proteomica e Biomolecolare, ISA-CNR, Via Roma 52 a, Avellino 83100, Italy. Electronic address: mamone@isa.cnr.it.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Mamone
authors.affiliation: Dipartimento di Agraria, Università di Napoli "Federico II", Parco Gussone, Portici (Napoli) 80055, Italy. Electronic address: ferranti@unina.it.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Ferranti
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Via S. Pansini, 5, Napoli 80131, Italy. Electronic address: palumbo@unina.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palumbo
authors.affiliation: Dipartimento di Medicina e Scienze della Salute, Università del Molise, Via De Sanctis, snc, Campobasso 86100, Italy. Electronic address: gentilefabrizio@unimol.it.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Gentile
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle / Q000378:metabolism*; D007455:Iodine / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013954:Thyroglobulin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014284:Triiodothyronine / Q000096:biosynthesis* / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D014284:Triiodothyronine; D014443:Tyrosine; D013954:Thyroglobulin; D007455:Iodine
keywords: Dehydroalanine; Donor tyrosine; Hormonogenic tyrosine; Mass spectrometry; Thyroglobulin; Thyroid hormone synthesis