Dependence on cations for the binding activity of lectins as determined by affinity electrophoresis

The metal ion content of eighteen different lectins was determined. The lectins were demetallized and the binding activity of native and demetallized forms were investigated using non-denaturing polyacrylamide affinity gel electrophoresis. The binding activities of all lectins were dependent on their metal ion content; when the cations were removed the lectins lost their carbohydrate binding activity. There was a marked difference in the strength with which lectins bind divalent cations.