Chromatographic behaviour of glucose 1- and 2-oxidases from fungal strains on immobilized metal chelates

Abstract

Glucose 2-oxidase from Coriolus versicolor and Phanerochaete chrysosporium and glucose 1-oxidase from Aspergillus niger bound to a CU(II)-IDA column in the pH range of 6-8. However, glucose 1-oxidase from Penicillium amagasakiense bound only partially to a CU(II)-IDA column at pH 8.0. Metal chelates containing either Ni(II) or Zn(II) were useful in the adsorption of glucose 2-oxidase from Phanerochaete chrysosporium. The binding of glucose 2-oxidase from P. chrysosporium to Ni(II) and Zn(II)-IDA agarose columns increases as a function of pH of the buffer system. The adsorption of glucose oxidases on metal(II))-IDA chelates was due to the available histidine residues on enzyme molecules since the addition of imidazole in the buffer system abolished the binding of glucose oxidases to these columns. Both glucose oxidases from C. versicolor, P. chrysosporium and A. niger were purified in one step by immobilized metal affinity chromatography on metal(II)-IDA agarose columns with a recovery of enzyme activity in the range of 80-91%. Purified preparations of glucose oxidases from fungal strains were apparently homogeneous on native PAGE and SDS-PAGE. Immobilized metal affinity chromatography was used to separate glucose 1-oxidase from the 2-oxidase on metal(II)-IDA agarose columns which was confirmed by analysis of the reaction products by HPLC. The different chromatographic behaviour of glucose oxidases on metal(II)-IDA chelates is apparently due to the number and spatial distribution of available histidine residues on these enzyme molecules.