INTERACTION OF ORGANIC AND INORGANIC PHOSPHATES WITH HEMOGLOBIN

The interaction of human deoxy-, oxy-, and methemoglobin with 2,3-diphospho-glycerate, adenosine tri-, di-, and monophosphates, ribose-5-phosphate, pyrophosphate, tripolyphosphate and tetra-, and hexametaphosphate was studied by equilibrium dialysis in a cacodylate buffer (.05 m cacodylic acid, Γ 2 0.033, pH 6.5). The experimental data were analyzed to determine the binding sites and association constants. Adenosine monophosphate and ribose-5-phosphate were bound in negligible amounts. In the remaining experiments, the first class (k1) consisted of one site with a high association constant; the second class (k2) was characterized by two to four sites with lower association constants. An additional class was obtained for tripolyphosphate and hexametaphosphate. The degree of binding was generally lower in the oxyhemoglobin but the differences in the values for the respective hemoglobins were not marked. Information concerning the sites bound could not be derived from these experiments. © 1969.