Amino-acid Sequences and Functional Differentiation of Hemoglobins A and D from Swift(Apus apus,Apodiformes)

Abstract
The blood of the adult swift contains one major (HbA = .alpha.2A.beta.2) and two minor components (HbD = .alpha.2D.beta.2 and HbD''). The components were separated by FPLC with a TSK SP-5 PW-column in phosphate buffers, and were eluted with a linear NaCl gradient. HbD'' could be detected only in freshly prepared hemolysates with the sensitive FPLC separation method. The globin chains were separated on a cation exchanger (CM-cellulose), the tryptic peptides by HPLC with a RP-2 LiChrosorb column. Their amino-acid sequences were determined by automatic Edman degradation with the film- or gasphase method. For the .alpha.A-, .alpha.D- and .beta.-chains, peptide alignment was achieved by homologous comparison with the corresponding chains of the greylag goose (Anser anser). The structural significance of the substitutions was examined with the aid of molecular graphics. The oxygen-binding properties of the stripped hemolysate and of HbA HbD and their dependence on pH, temperature and inositol polyphosphate are presented and discussed with reference to molecular structures and hypothermy that occurs during torpidity.

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