A qualitative examination of the GST proteome of the blow fly, Lucilia cuprina: Use of cross-database matching of MALDI data

This study was aimed at determining whether, in the absence of a full genetic database for the Sheep Blowfly (Lucilia cuprina) glutathione transferases from this insect could be characterized by cross-database matching of MALDI TOF data with the database for other metazoan organisms. Glutathione transferases of L. cuprina were partially purified by the sequential use of affinity chromatography media; first on glutathione immobilized on epichlorohydrin-activated Sepharose 6B and subsequently on dinitrophenyl-glutathione immobilized on the same matrix. The Proteins obtained were separated by 2D SDS-PAGE and tentatively characterized by MALDI-TOF analysis of tryptic peptides. The mass fragments were matched against the NCBInr “Other metazoa” database. The GSTs matched to other insect species were identified as coming from the Sigma, Delta and Epsilon classes. The relative abundance of most of these GSTs appeared to vary little during development, or across bodily segments, an exception being one group, (Zone E) tentatively identified as Epsilon class, which was most prominent in eggs and absent from adults and which is therefore assumed to play a specific role in development.