Some divalent cations (at 10(-3)M concentration) have been shown to act as oxygen-linked ligands. The effect of Ca++ (only on hemoglobin S) and Zn++ (on normal hemoglobin and hemoglobin S) can be traced to a preferential binding of these cations to the oxy- conformation of the proteins; the reverse is true for Ni++, since its presence reduces the oxygen affinity of both hemoglobins. The results suggest: i) the existence of at least two different cation binding sites on hemoglobin; ii) the replacement of glutamic acid by valine in hemoglobins S introduces sufficient structural modification to form a new cation binding site.
Amiconi, G., Civalleri, L., Condo', S.g., Ascoli, F., Santucci, R., Antonini, E. (1981). Evidence for multiple differing cation binding sites on hemoglobin A and S. HEMOGLOBIN, 5(3), 231-240.
Evidence for multiple differing cation binding sites on hemoglobin A and S
CONDO', SAVERIO GIOVANNI;SANTUCCI, ROBERTO;
1981-01-01
Abstract
Some divalent cations (at 10(-3)M concentration) have been shown to act as oxygen-linked ligands. The effect of Ca++ (only on hemoglobin S) and Zn++ (on normal hemoglobin and hemoglobin S) can be traced to a preferential binding of these cations to the oxy- conformation of the proteins; the reverse is true for Ni++, since its presence reduces the oxygen affinity of both hemoglobins. The results suggest: i) the existence of at least two different cation binding sites on hemoglobin; ii) the replacement of glutamic acid by valine in hemoglobins S introduces sufficient structural modification to form a new cation binding site.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.