Structure and function of hemoglobin in antarctic fishes and evolutionary implications

The hematological features of cold-adapted, red-blooded Antarctic teleosts has prompted this study on the relationship between hemoglobin molecular structure and oxygen-binding properties. The hemolysates from 21 species of 5 families contained one component (Hb 1), often accompanied by an additional, minor one (Hb 2, 5%-10% of total). On the other hand, 3 species of Zoarcidae, a non-endemic family, had 4-5 components. All purified hemoglobins from the former group, but only 1-2 of the 4-5 hemoglobins of Zoarcidae, showed a strong Root effect (pH regulation of oxygen binding). Globins from each hemoglobin have been purified and characterised with respect to molecular structure in several species. The similarity between the complete amino acid sequence of one ?-chain and those of non-Antarctic ?-chains is lower than that among the latter sequences, suggesting independent pathways of evolution. © 1990 Springer-Verlag.