| Popis: |
Unlike the majority of mammals, which produce only a single major haemoglobin (Hb) component (>90% of the Hb content of the red blood cell), many fish species have multiple Hb components which show considerable differences in sequence and functional properties. Functional heterogeneity of several Hb types within the red cell can extend the range of conditions under which oxygen can be transported effectively around the blood stream, and permits a division of labour between the various components which can each fulfil a specific role. A number of fish Hbs are known to show very low oxygen affinity as pH drops, but the structural basis for this effect is only recently becoming clear. Site-directed mutagenesis and functional studies are described, comparing the Hbs of Trematomus bernachii and Trematomus newnesi. |
