Interaction of allosteric effectors (ATP,CO2, H+) modulating oxygen affinity of the hemoglobin in the carp,Cyprinus carpio,in vitro |
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Authors: | Th. Wurm C. Albers |
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Affiliation: | (1) Institut für Physiologie, Universität Regensburg, Postfach 31, D-8400 Regensburg, Federal Rebulic of Germany |
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Abstract: | Summary The interaction of allosteric effectors (CO2, ATP, H+) with respect to the oxygen affinity of carp hemoglobin was analyzed by determining oxygen binding curves spectrophotometrically in dilute solutions of stripped hemoglobin at 20°C. The pH range studied was 6.8–8.2.PCO2 was 0, 10 and 70 mmHg (0, 1.33 and 9.3 kPa). ATP/Hb4 was 0, 8 and 24. In the presence of either CO2 or ATP, the effects of the cofactors onP50 were as expected over the whole pH range. In contrast to other published data, each cofactor also had a significant effect onP50 in the presence of the other cofactor. Evidence was obtained that oxylabile carbamate is formed by carp hemoglobin and that the formation of carbamate persists at a lower level in the presence of ATP. The results support the view that the binding of ATP to carp hemoglobin requires only one terminal amino group, leaving the other N-terminal of the -chain free to react with CO2. |
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Keywords: | Carp hemoglobin Oxygen affinity ATP CO2 |
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