Carnivora: the primary structure of Weddell Seal (Leptonychotes weddelli, Pinnipedia) hemoglobin

The hemoglobin of Weddell Seal (Leptonychotes weddelli, Pinnipedia) comprises two components with identical beta-chains. The alpha-chains differ in positions 15 (Gly/Asp) and 57 (Ala/Thr). We present the primary structure of the chains which have been separated by reversed-phase high-performance liquid chromatography. The sequences have been determined by automatic Edman-degradation with the film-technique or the gas-phase method, using the native chains and the tryptic peptides of the oxidized chains. Compared to the corresponding human chains we found 22 substitutions in the alpha-chains and 14 in the beta-chains. In the alpha-chains exchanges involve one heme- and three alpha 1/beta 1-contacts. In the beta-chains one heme contact, one alpha 1/beta 1- and one alpha 1/beta 2-contacts are substituted. The sequences are compared to those of other Pinnipedia and Arctoidea hemoglobins.