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PURIFICATION AND CHARACTERIZATION OF β‐GLUCOSIDASE FROM GREATER WAX MOTH Galleria mellonella L. (LEPIDOPTERA: PYRALIDAE)

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Archives of Insect Biochemistry and Physiology

Published online on

Abstract

The greater wax moth, Galleria mellonella, is one of the most ruinous pests of honeycomb in the world. Beta‐glucosidases are a type of digestive enzymes that hydrolytically catalyzes the beta‐glycosidic linkage of glycosides. Characterization of the beta‐glucosidase in G. mellonella could be a significant stage for a better comprehending of its role and establishing a safe and effective control procedure primarily against G. mellonella and also some other insect pests. Laboratory reared final instar stage larvae were randomly selected and homogenized for beta‐glucosidase activity assay and subsequent analysis. The enzyme was purified to apparent homogeneity by salting out with ammonium sulfate and using sepharose‐4B‐l‐tyrosine‐1‐naphthylamine hydrophobic interaction chromatography. The purification was 58‐fold with an overall enzyme yield of 29%. The molecular mass of the protein was estimated as ca. 42 kDa. The purified beta‐glucosidase was effectively active on para/ortho‐nitrophenyl‐beta‐d‐glucopyranosides (p‐/o‐NPG) with Km values of 0.37 and 1.9 mM and Vmax values of 625 and 189 U/mg, respectively. It also exhibits different levels of activity against para‐nitrophenyl‐β‐d‐fucopyranoside (p‐NPF), para/ortho‐nitrophenyl β‐d‐galactopyranosides (p‐/o‐NPGal) and p‐nitrophenyl 1‐thio‐β‐d‐glucopyranoside. The enzyme was competitively inhibited by beta‐gluconolactone and also was very tolerant to glucose against p‐NPG as substrate. The Ki and IC50 values of δ‐gluconolactone were determined as 0.021 and 0.08 mM while the enzyme was more tolerant to glucose inhibition with IC50 value of 213.13 mM for p‐NPG.