The Effect of þH on the Combination of Serum Albumin with Metals

Abstract

A polarographic study has been made of the effect of þH upon the interaction between a number of metals and bovine serum albumin. It is concluded that the principal sites on the protein molecule responsible for metal binding are the imidazole groups. Approximate values of the logarithms of the intrinsic association constants with these groups are: Cu++ (in 0.15 M KNO3) 3.7, Zn++ (in 0.15 M KCl) 2.9, Cd ++ (in 0.15 M KCl), 2.8, Pb++ (in 0.15 M KNO3) < 2.3, Tl+ (in 0.15 M KCl) < 0. Weak binding also occurs at carboxyl groups. The extent of binding at these sites is determined largely by the competitive effect of other anions present in solution. © 1952, American Chemical Society. All rights reserved.