title: Carbohydrate analysis of porcine thyroglobulin isoforms with different iodine contents.
abstract: To further validate the relationship between thyroid hormone formation and the carbohydrate structure of thyroglobulin (Tg), we reinvestigated the relationship between the iodine content and the asparagine-linked oligosaccharide structures of porcine Tg. Purified porcine Tg was further separated into isoforms (Tg-F1, -F2 and -F3) with a DEAE-cellulose ion-exchange chromatography column. The iodine residues, neutral sugar and sialic acid were analyzed for the separated Tg isoforms and their asparagine-linked oligosaccharide structures were analyzed. The asparagine-linked oligosaccharides were released from Tg-F1, -F2 and -F3 by hydrazinolysis and each oligosaccharide was labeled with p-aminobenzoic acid octyl ester (ABOE). The ABOE-labeled oligosaccharides from Tg-F1, -F2 and -F3 were analyzed for their relative content in oligosaccharides of each structure type by chemical methods and DEAE- and ConA high-performance liquid chromatography (HPLC) columns. As a result, it was revealed that the Tg fraction eluted at higher ionic strength from a DEAE-cellulose column is apt to contain more of each iodoamino acid, as well as total content of iodine, larger negative zeta-potential, conforming to sialic acid content in the Tg molecule and to a higher content of di-sialo-bi-antennary complex and to high mannose type oligosaccharides. These results support the conclusion that iodine organification of the Tg molecule is correlated with asparagine-linked oligosaccharide completion.
authors.affiliation: Department of Applied Biology, Faculty of Science and Technology, Science University of Tokyo, Chiba, Japan. masalab@rs.noda.sut.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Ikekita
authors.forename: H
authors.initials: H
authors.lastname: Yajima
authors.forename: T
authors.initials: T
authors.lastname: Murata
authors.forename: K
authors.initials: K
authors.lastname: Takatera
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Sonoyama
authors.forename: Y
authors.initials: Y
authors.lastname: Tezuka
authors.forename: T
authors.initials: T
authors.lastname: Ishii
authors.forename: O
authors.initials: O
authors.lastname: Tarutani
mesh_terms: D000818:Animals; D001216:Asparagine; D002241:Carbohydrates / Q000032:analysis; D002848:Chromatography, DEAE-Cellulose; D002851:Chromatography, High Pressure Liquid; D007455:Iodine / Q000032:analysis*; D013058:Mass Spectrometry; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D012794:Sialic Acids / Q000032:analysis; D013552:Swine; D013954:Thyroglobulin / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D002241:Carbohydrates; D009844:Oligosaccharides; D012794:Sialic Acids; D001216:Asparagine; D013954:Thyroglobulin; D007455:Iodine