The kinetics and equilibria of squirrel-fish hemoglobin. A Root effect hemoglobin complicated by large subunit heterogeneity.
The functional properties of squirrel-fish hemoglobin have been measured by studying ligand binding equilibria and kinetics. The results show that squirrel-fish hemoglobin has a Root effect with a corresponding stabilization of the low affinity state. The properties of this state are pH dependent even in the absence of cooperativity. The effect of ATP shifts the overall ligant affinity towards the low affinity state and is characteristic of the allosteric effect caused by organic phosphates. Under pH and ATP conditions favoring the low affinity conformational state, a 10-fold difference in the binding kinetics of carbon monoxide to the alpha and beta subunits is observed.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000494:Allosteric Regulation; D000818:Animals; D002248:Carbon Monoxide / Q000097:blood; D002263:Carboxyhemoglobin / Q000378:metabolism*; D005399:Fishes / Q000097:blood*; D006454:Hemoglobins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism*
D006454:Hemoglobins; D008024:Ligands; D010108:Oxyhemoglobins; D002248:Carbon Monoxide; D000255:Adenosine Triphosphate; D002263:Carboxyhemoglobin; D010100:Oxygen