Striped mullet (Mugil cephalus) hemoglobin system: multiplicity and functional properties

Massimo Castagnola, Bruno Giardina, A Olianas, C Meloni, I Messana, Mt Sanna, B Manconi, S Salvadori, M. Pellegrini

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The most frequent (90\%) phenotype of the hemoglobin system of M. cephalus presented two major hemoglobins, the more anodal HbI accounting for approximately 70\% of the total. The two hemoglobin components separated by ion-exchange chromatography were analyzed by reverse-phase HPLC and electrospray ionization-mass spectrometry which revealed a more complex pattern: HbI consists in four different globins, two beta (named beta 1 and beta 3) and two co-eluting alpha chains (alpha 1 and alpha 2); HbII consists in three globins, one beta chain (named beta 2) and the same alpha 1 and alpha 2 present in HbI. The oxygen-binding properties of both hemoglobin components purified by DEAE cellulose were almost identical to those of the hemolysate: stripped hemoglobin showed a large Bohr effect which was enhanced by chloride ions and, at a larger extent, by organic phosphates which, at acidic pH values gave rise to the Root effect. A series of oxygen-binding experiments at increasing GTP concentrations was carried out in order to compare GTP-binding activities in the absence and presence of physiological amounts of chloride. The results indicated that hemoglobin do have two sites for GTP binding. In the absence of chloride, the two sites cannot be discriminated, whereas in the presence of chloride, a competition between the two anions occurred for both GTP-binding sites. The presence of multiple hemoglobin components with identical properties confirms that hemoglobin heterogeneity that often occurs in fish cannot be only explained as an evolutionary response to the physiological and/or environmental needs of the species.
Original languageEnglish
Pages (from-to)187-197
Number of pages11
JournalJOURNAL OF COMPARATIVE PHYSIOLOGY. B, BIOCHEMICAL, SYSTEMIC, AND ENVIRONMENTAL PHYSIOLOGY
Volume181
DOIs
Publication statusPublished - 2011

Keywords

  • Bohr effect
  • Electrospray ionization-mass spectrometry

Fingerprint

Dive into the research topics of 'Striped mullet (Mugil cephalus) hemoglobin system: multiplicity and functional properties'. Together they form a unique fingerprint.

Cite this