Partial Biochemical Characterization and Iron Binding Capacities of Transferrin Variants of Air-breathing Murrel Channa punctata (Channidae: Channiformes)

Abstract

Partial biochemical characterization of highly purified homozygous serotransferrin (Tf) phenotypes AA, BB and CC of air-breathing murrel, Channa punctata, was conducted. Molecular weight of each pure Tf variant was 75 kDa. Each Tf variant also had sialic acid as carbohydrate moiety of 10.5 kDa. Difference in spectra of ironapotransferrin complexes of C. punctata and human Tf were similar. Complex of each apoTf with iron had its maximum at 460 nm. Lack of a shoulder at 480 nm was characteristic of TfBB, while TfCC and TfAA had one shoulder at 480 nm and the other at 510 nm. The TfBB also had the highest total iron-binding capacity followed by TfCC and TfAA, respectively, though total saturation for each Tf was reached at 14 μM FENTA. Interestingly, the relative total iron-binding capacities of TfBB and CC showed a positive correlation with the allelic composition of populations, which were the sources of sera. The significance of iron binding capacities of Tf variants along with some other factors on the population structure of C. punctata is discussed.