Herbert, Neill A3; Skov, Peter V4; Wells, Rufus M G3; Steffensen, John F5
1 Freshwater Biology, Department of Biology, Faculty of Science, Københavns Universitet2 Marine Biology, Department of Biology, Faculty of Science, Københavns Universitet3 unknown4 Freshwater Biology, Department of Biology, Faculty of Science, Københavns Universitet5 Marine Biology, Department of Biology, Faculty of Science, Københavns Universitet
The relationship between whole blood-oxygen affinity (P(50)) and pH-dependent binding (i.e., cooperativity and the Bohr [ Phi ] and Root effects) was examined statistically under standardized conditions (10.0 degrees Celsius) in four unrelated cold-temperate marine fishes that differ widely in their swimming performance and their expected responses to hypoxia: cod (Gadus morhua), herring (Clupea harengus), mackerel (Scomber scombrus), and plaice (Pleuronectes platessa). An unexpected difference in blood-oxygen affinity was found (herring>plaice>mackerel>cod), and this was independent of both swimming performance and the predicted low O(2) response of each species. The ecotype of the four marine species was also unrelated to pH-dependent binding because no difference in the Bohr effect was apparent ( Phi varied insignificantly from -0.90 to -1.06), and differences in the magnitude of the cooperative binding reaction were associated only with the presence of the Root effect. Although several reviews propose a generalized link between blood-oxygen affinity and pH-dependent binding, our results advise against overestimating the adaptive functional properties of hemoglobin across unrelated species.
Physiological and Biochemical Zoology, 2006, Vol 79, Issue 5, p. 909-18