Primary structure of hemoglobin from trout (Salmo irideus). Amino acid sequence of alpha chain of Hb trout I.

The amino acid sequence of the alpha chain of the hemoglobin component of trout's blood which is devoid of heterotropyc phenomena, i.e. Hb trout I, is presented. The sequence has been determined by analyzing the soluble tryptic peptides obtained from the whole globin and the peptides obtained after redigesting the insoluble 'core' with chymotrypsin. Alignment of the peptides with the structure of human as well as carp and Catostomus clarkii alpha chains shows that Hb trout I alpha chain differs from the corresponding human protein by 43% amino acid substitutions and from the two other fish by 34.5% and 33.1%, respectively. Further comparison of sequence data available for the N-terminal region suggests that the divergence between Hb trout I and IV, the other major hemoglobin component of trout's blood, is greater than that found between each trout hemoglobin and the other two fishes (carp and C. clarkii.).