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Functional studies on the separated hemoglobin components of an air-breathing catfish,Hoplosternum littorale (Hancock)

1979; Elsevier BV; Volume: 62; Issue: 1 Linguagem: Inglês

10.1016/0300-9629(79)90759-x

0300-9629

Robert Garlick, H. Franklin Bunn, H. J. Fyhn, Unni E.H. Fyhn, Joseph P. Martin, Robert W. Noble, Dennis A. Powers,

Neonatal Health and Biochemistry

1. The two hemoglobins, Hb I and II, of the obligate air-breathing catfish,Hoplosternum littorale have been isolated. 2. The unfractionated stripped hemoglobin has a high oxygen affinity, a normal alkaline Bohr effect, and a Root effect. 3. Both the Bohr and Root effects are enhanced by 1 mM ATP. 4. Stripped Hb I has a relatively high oxygen affinity, a reversed Bohr effect between pH 6.0 and 8.0 (Δlog P50†DpH> 0), but no Root effect. Addition of 1 mM ATP to Hb I causes a marked reduction in the oxygen affinity, a change to a normal alkaline Bohr effect (Δlog P50ΔpH< 0), but no Root effect. 5. Stripped Hb II has a lower oxygen affinity at low pH and a higher oxygen affinity at high pH than does Hb I. Hb II shows a large alkaline Bohr effect which is only slightly increased by 1 mM ATP and a Root effect at low pH which is enhanced by 1 mM ATP. 6. The observed rates of O2 dissociation and of CO combination with Hbs I and II show differences which parallel those observed in the oxygen equilibrium measurements.