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GSH S-Transferases of Insect Pests

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dc.contributor.author Drake, Beryl
dc.date.accessioned 2008-09-02T00:10:04Z
dc.date.accessioned 2022-11-02T20:59:45Z
dc.date.available 2008-09-02T00:10:04Z
dc.date.available 2022-11-02T20:59:45Z
dc.date.copyright 1982
dc.date.issued 1982
dc.identifier.uri https://ir.wgtn.ac.nz/handle/123456789/29062
dc.description.abstract The purification of GSH S-transferases from Wiseana larvae is described. The purification procedure developed was DE-32 cellulose chromatography, affinity chromatography on GSH-BSP coupled to epichlorohydrin-activated sepharose 4B, CM-cellulose chromatography and preparative isoelectric focusing. Glutathione S-transferase IVb was purified to apparent homogeneity as judged by disc electrophoresis, SDS-electrophoresis and isoelectric focusing. The protein had an isoelectric point of 7.91. A partially pure enzyme, GSH S-transferase I, on preparative isoelectric focusing yielded two enzyme fractions Ia and Ib. The most active fraction, Ib, had an isoelectric point of 6.62. The molecular weight of GSH S-transferases I and IV was estimated to be 40,000. SDS-electrophoresis revealed a single band of molecular weight of 25,500 for GSH S-transferase I and 22,900 for GSH, S-transferase IV, indicating that the enzymes are each composed of two subunits of approximately equal size. The optimum pH for enzyme activity was 8.0 to 8.5 for both GSH.S-transferase I and IV. Both enzymes are active for CDNB, DCNB, ethacrynic acid and iodomethane conjugation but were inactive for 4-nitropyridine-N-oxide, 1, 2-epoxy-3-(P-nitrophenoxy)propane, BSP and P-nitrobenzyl chloride conjugation. GSH S-transferase IV has no detectable activity with the insecticides methyl parathion and diazinon. Despite similar physical properties GSH S-transferases I and IV are not immunologically related. GSH S-transferase IV was shown to have a hiqh content of the amino acids lysine, aspartic acid, glutamic acid and leucine. The kinetics of GSH S-transferase IV are complex and resemble those reported for GSH S-transferase A from rat liver, except that the enzyme activity is inhibited by the product, chloride ion. The localisation method utilising polyacrylamide-starch gels and the substrate iodomethane was developed for the detection of GSH S-transferase activity. en_NZ
dc.format pdf en_NZ
dc.language en_NZ
dc.language.iso en_NZ
dc.publisher Te Herenga Waka—Victoria University of Wellington en_NZ
dc.title GSH S-Transferases of Insect Pests en_NZ
dc.type Text en_NZ
vuwschema.type.vuw Awarded Doctoral Thesis en_NZ
thesis.degree.discipline Biochemistry en_NZ
thesis.degree.grantor Te Herenga Waka—Victoria University of Wellington en_NZ
thesis.degree.level Doctoral en_NZ
thesis.degree.name Doctor of Philosophy en_NZ

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