Twenty-five years of immobilized metal ion affinity chromatography: past, present and future.

Aspergillus as a host for heterologous protein production: the problem of proteases

, model integration of the bibliome, genome, metabolome and reactome of Aspergillus niger

Pseudobiospecific ligand affinity chromatography

This review discusses the principles of immobilized metal ion affinity chromatography (IMAC) and its applications to protein separations. IMAC functions by binding the accessible electron-donating pendant groups of a protein - such as histidine, cysteine, and tryptophan - to a metal ion which is held by a chelating group covalently attached on a stationary support. A common chelating group is iminodiacetate. The ions commonly used are of borderline or soft metals, such as Cu2+, Ni2+, Co2+, and Zn2+. Protein retention in IMAC depends on the number and type of pendant groups which can interact with the metal. The interaction is affected by a variety of independent variables such as pH, temperature, solvent type, salt type, salt concentration, nature of immobilized metal and chelate, ligand density, and protein size. Proteins are usually eluted by a decreasing pH gradient or by an increasing gradient of a competitive agent, such as imidazole, in a buffer. There are still several unresolved issues in...

Sivadasan Krishnan

Papers

Purification of an acid protease and a serine carboxypeptidase from Aspergillus niger using metal-chelate affinity chromatography.

Purification and some properties of three serine carboxypeptidases from aspergillus niger

Semi-preparative-scale isolation of carboxypeptidase iso-enzymes from aspergillus niger by a single metal chelate affinity chromatographic step