Interaction of glucose oxidase with blue dextran

Abstract

The preparation and properties of a glucose oxidase-Blue Dextran complex are described. At pH 7.4, in 0.1 M phosphate buffer, glucose oxidase and Blue Dextran interact strongly with each other. Under these conditions a soluble complex is formed, as shown by ultrafiltration experiments using a Diafio XM-300 membrane (nominal molecular weight cut-off 300,000). In this complex, the enzyme is about 40% more active than when free in solution, and is also more stable towards acid denaturation. Comparative studies were carried out using a high-molecular-weight Dextran fraction devoid of dye residues (Dextran T-2000). The results obtained suggest that the dye moiety of Blue Dextran is directly involved in the binding of the protein, and possibly also in the enhancement of its enzymatic activity.