The Important Role of Enzyme Adsorbing Capacity of Soil Minerals in Regulating β-Glucosidase Activity

Abstract

Mineral surfaces are known for their ability to adsorb enzymes, but their effects on enzyme activity are not well studied. This study explores the extent to which interaction with primary silicates and secondary minerals affects the activity and longevity of a model soil enzyme β-glucosidase (BG). The BG activity was correlated with the capacity-related properties of minerals (controlling space for adsorption), including specific surface area (SSA) and the SSA-normalized amount of BG adsorption, but not with the functional properties (controlling the mechanisms of adsorption) such as surface charge. BG conformational change is a function of SSA-normalized amount of adsorption, suggesting that spatially more distributed enzyme molecules would have a higher probability of encounter with the substrate than the congested molecules. The highest decay rate of BG activity was observed in the presence of Mn-oxide. Our results shed new light on the effect of mineral surface on enzyme activity.