Salicylaldehyde-metal-amino acid ternary complex: a new tool for immobilized metal affinity chromatography

An immobilized salicylaldehyde (sal) was used to build various salicylaldehyde-copper-amino acid (Sal-Cu-AA) complexes which are stable at a range of pH values (2.0-11.0). The complexes were found to bind protein molecules as IMAC resins. Thirteen proteins were examined for their binding to a Sal-Cu-Gly column. The efficacy of the Sal-Cu-AA resin for protein separation were demonstrated by two examples. The first was a new purification process for garlic lectins from garlic crude extract. It seems that in this case the Sal-Cu-AA resins were more selective than IDA resin. The second was immobilization of concanavalin A (Con A) on the resin and using the immobilized Con A for affinity chromatography of mannose-rich glycoprotein ovalbumin. The Con A could be later eluted with EDTA or imidazole and the Sal-containing polymer could be recharged again for further use.