An Effective Method of Screening Glucose-rich Microbial Culture Filtrates for Insect Trehalase Inhibitors

Trehalase inhibitors are promising as a specific insect growth regulator. Microbial culture filtrates are a good source of bioactive compounds, but some of them retain a significant amount of glucose, a major component of the culture medium, which makes it difficult to detect trehalase inhibitors because of high blank values for the glucose determination. To find a variety of trehalase inhibitors in glucose-rich microbial culture filtrates, an effective method for removing glucose by enzymatic conversion prior to a routine trehalase-inhibitory assay was devised. Conversion with glucose oxidase and catalase could completely remove 10mg/ml of glucose, and a wide variety of microbial culture filtrates with high glucose content could then be subjected to the routine bioassay. This method can also be applied to screen inhibitors for other enzymes whose activity is assayed by the amount of glucose formed.