Study On The Modification Of Glucose Oxidase With Galactose

Glucose Oxidase is an aerobic dehydrogenase,which can specifically catalyzesβ-D- glucose,and has been widely applicated in food,feedstuff,medicine and other fields.In this study,a monoaminated galactose derivative was attached to glucose oxidase(GOD) to modify it via a carbodiimide-catalyzed reaction.Ricinus agglutinin affinity chromatography was first adopted to separate the modified and non-modified enzyme.The results showed that,as a galactose-binding protein,ricinus communis agglutinin could bind well with the modified enzyme(galactose-binding GOD, Gal-GOD) and could purify it from reaction mixture.The modification rate of GOD reached 80%via the calculation using the integral proportion method with N2000 chromatography data system.The modified GOD was confirmed by absorption and fluorescence spectroscopy.Comparing to that of GOD,the absorption peak of modified GOD at 380nm disappeared,and the absorption peak at 280nm became weaker and wider;the result of fluorescence spectroscopy showed that the character emission peak of tryptophane residue at 340nm had a obvious decrease and redshift. The thermostability of modified GOD was enhanced,based on the examination of enzymatic activity.Under a higher temperature such as at 55℃,the catalytic activity of modified GOD has been enhanced as high as 7.28 folds.This study laid a foundation for widening application of GOD.