Purification and characterization of a novel sigma-class glutathione S-transferase of the fall webworm, Hyphantria cunea

An enzyme that possesses glutathione S-transferase (GST) activity was found in the fall webworm, Hyphantria cunea. The enzyme was purified to homogeneity for the first time by ammonium sulphate fractionation and affinity chromatography. The N-terminal sequence of the purified protein was similar to those of Sigma-class GSTs. The purified GST retained more than 75% of its original GST activity after incubation at pH 5-8. Incubation for 30 min at temperatures below 50 degrees C scarcely affected the activity. The enzyme was able to catalyse the reaction of glutathione with 1-chloro-2,4-dinitrobenzene, a universal substrate for GST, as well as with 4-hydroxynonenal, a product of lipid peroxidation.