Metal ion-promoted binding of proteins to immobilized triazine dye affinity adsorbents

Abstract

Low concentrations of metal ions, particularly those of the first row transition series such as Zn 2 +, Co 2 +, Mn 2 +, Ni 2 +, Cu 2 +, and, to a lesser extent, the group IIA ions, Ca 2 + and Mg 2 +, promote the binding of proteins to a number of immobilized triazine dye affinity adsorbents. For example, Zn 2 + promotes binding of carboxypeptidase G2, alkaline phosphatase and yeast hexokinase to immobilized Procion Red H-8BN, Procion Yellow H-A and Cibacron Blue F3G-A respectively. The binding of ovalbumin to immobilized Cibacron Blue F3G-A and Procion Orange MX-G is selectively enhanced in the presence of Al 3 +. With ovalbumin and alkaline phosphatase, the effect is almost totally specific for both the metal ion and dye, whereas with carboxypeptidase G2 and hexokinase, metal ions such as Co 2 +, Ni 2 +, Mn 2 +, Cu 2 +, Ca 2 + and Mg 2 + also promote binding to varying degrees. Almost all other monovalent and trivalent metal ions appear to be ineffective. Metal ion-bound enzymes can subsequently be eluted with appropriate chelating agents of the amine, aminocarboxylate or substituted pyridine classes.