Characterization of serum immunoglobulin M of the Antarctic teleost Trematomus bernacchii

Biagio Pucci, Maria Rosaria Coscia, Umberto Oreste

Research output: Contribution to journalArticle

Abstract

Trematomus bernacchii immunoglobulin M concentration was determined in the serum by ELISA; the mean concentration value was 2.7 mg/ml corresponding to 9.6% of the total serum proteins. Purified IgM was analyzed by SDS-polyacrylamide gel electrophoresis, isoelectrofocusing and 2D electrophoresis. The relative molecular mass of the polymeric form was 830 kDa; that of separated H and L chains was, respectively, 78 and 25 kDa. The isoelectric points of the entire molecule ranged from 4.4 to 6.5, that of isolated H chains was between 4.0 and 6.0. Separated H chains were shown to reaggregate in tetrameric form. The cleavage site of trypsin was at the end of the CH1 domain, as confirmed by the N-terminal amino acid sequence of one of the resultant peptides. Immunoblotting was used to detect carbohydrates in the H and L chains labeled with digoxigenin. Glycosyl residues were detected only in the H chain. The carbohydrate content was evaluated to be 12.8% of the entire chain. Purified Igs were hydrolyzed by N-glycosidase F at different conditions and at least four different hydrolytic sites were revealed by limited deglycosylation. T. bernacchii IgM was also compared to those of five other polar fish species.

Original languageEnglish
Pages (from-to)349-357
Number of pages9
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Volume135
Issue number2
DOIs
Publication statusPublished - Jun 1 2003

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Keywords

  • 2D electrophoresis
  • Antarctica
  • Cold adaptation
  • Deglycosylation
  • ELISA
  • Immunoglobulin M
  • Teleost
  • Trematomus
  • Trypsinolysis

ASJC Scopus subject areas

  • Biochemistry
  • Physiology

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