Copper and zinc ion binding by bovine, dog, and rat serum albumins.

An ultrafiltration technique was used to study stripping by glycine of the first copper and zinc ion equivalents bound by bovine, dog, and rat serum albumins at pH 7.5. Affinity of dog serum albumin for copper was poorer than for the other albumins, consistent with the absence in the former albumin of the copper binding site present at the amino terminus of the latter albumins. Affinities of all three proteins for zinc were similar, suggesting that the albumin amino terminus is not the primary zinc ion binding site.