Isolation, cloning and sequencing of transferrins from red-eared turtle, African ostrich, and turkey

Transferrins form an important class of iron-binding proteins widely distributed in the physiological fluids of vertebrates and invertebrates. In vertebrates they are present mostly in serum as serotransferrins. In birds and reptiles transferrins are also found in eggs as ovotransferrins. However, until now only chicken and duck ovotransferrin sequences have been published. This paper presents data on the purification, biochemical analysis, cloning and sequencing of ovotransferrins from red-eared turtle, African ostrich and turkey, revealing their significant homology with other known ovotransferrin sequences. The proteins were purified by size-exclusion and anion-exchange chromatography. Isoelectric points, iron-saturated and iron-free spectra, as well as the mRNA nucleotide sequences of 2409 nt (ORF: 2106 nt encoding a 701-amino-acid polypeptide; AJ786651), 2418 nt (ORF 2118 nt encoding a 705-amino-acid polypeptide; AJ786650), and 2397 nt (ORF: 2118 nt encoding a 705-amino-acid polypeptide; AJ966469) were determined for ostrich (OtrF), red-eared turtle (TtrF), and turkey (MtrF) ovotransferrin, respectively.