The glutathione-S-transferases (GSTs) (EC.2.5.1.18) are enzymes that participate in cellular detoxification of endogenous as well as foreign electrophilic compounds, function in the cellular detoxification systems and are evolved to protect cells against reactive oxygen metabolites by conjugating the reactive molecules to the nucleophile scavenging tripeptide glutathione (GSH, & / #61543 / -glu-cys-gly). The GSTs are found in all eukaryotes and prokaryotic systems, in the cytoplasm, on the microsomes, and in the mitochondria. Cytosolic GSTs have been grouped into seven distinct classes as: alpha (& / #61537 / ), mu (& / #61549 / ), pi (& / #61552 / ), sigma (& / #61555 / ), omega, theta (& / #61553 / ) and zeta (& / #61540 / ).
In comparison with other GSTs, class theta enzymes have proven difficult to isolate and characterize. Two distinct theta GSTs have been identified in man, GSTT1-1 and GSTT2-2 three in the rat rGST1-1, rGSTT2-2 and 13-13 and one in
the mouse. this study, a class theta GST (GSTT2-2), with high activity towards 1-MS was isolated and purified from bovine liver in 3% yield with a purification factor of 3-fold. The purification protocol included a sequential DEAE cellulose anion exchanger liquid chromatography column, S-hexylglutathione agarose affinity column, dye binding orange A and chromatofocusing columns. The enzyme activity and protein content decreased rapidly after the last step of purification. The purified GSTT2-2 showed significant activity only towards 1-MS as 77 nmole/min/mg. The GSTT2-2 purified from bovine liver had a molecular weigth (Mr) value of about 28,200 which was also confirmed by Western Blott Analysis. The purified farctions of GSTT2-2 with other kolon farctions were tested with anti GSTT2-2, antiGST alfa, antiGST mu and antiGST pi antibodies. The enzyme activities towards CDNB, 4-nitrobenzylchloride (NBC) and 1-menapthyl sulfate were measured as described by Habig and Jacoby.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12604851/index.pdf |
| Date | 01 March 2002 |
| Creators | Isgor, Sultan Belgin |
| Contributors | Coruh, Nursen |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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