| 1 | Novel functional association of rat testicular membrane-associated cytosolic glutathione S transferases and cyclooxygenase in vitro显示文摘Aim: To analyze the role of cytosolic glutathione S-transferases (cGSTs) and membrane-associated cytosolic GSTs (macGSTs) in prostaglandin biosynthesis and to evaluate the possible interaction between glutathione S-transferases (GSTs) and cyclooxygenase (COX) in vitro. Methods: SDS-PAGE analysis was undertaken for characterization of GSTs, thin layer chromatography (TLC) to monitor the effect of GSTs on prostaglandin biosynthesis from arachidonic acid (AA) and spectrophotometric assays were done for measuring activity levels of COX and GSTs. Results:SDS-PAGE analysis indicates that macGSTs have molecular weights in the range of 25-28kDa. In a coupled assay involving GSTs, arachidonic acid and cyclooxygenase-1, rat testicular macGSTs produced prostaglandin E2 and F2α,while the cGSTs caused the generation of prostaglandin D2, E2 and F2α. In vitro interaction studies on GSTs and COX at the protein level have shown dose-dependent inhibition of COX activity by macGSTs and vice versa. This effect,however, is not seen with cGSTs. The inhibitory effect of COX on macGST activity was relieved with increasing concentrations of reduced glutathione (GSH) but not with 1-chloro 2,4-dinitrobenzene (CDNB). The inhibition of COX by macGSTs, on the other hand, was potentiated by glutathione. Conclusion: We isolated and purified macGSTs and cGSTs from rat testis and analyzed their involvement in prostaglandin biosynthesis. These studies reveal a reversible functional interaction between macGSTs and COX in vitro, with possible interactions between them at the GSH binding site of macGSTs. | S.Neeraja B.Ramakrishna A.S.Sreenath G.V.Reddy P.R.K.Reddy P.Reddanna | 2005 | Asian Journal of Andrology2005，7，2： | 1 |
| 2 | Purification and characterization of rat testicular glutathione S-transferases:role in the synthesis of eicosanoids显示文摘Aim: Purification of glutathione S-transferases (GSTs) from rat testis; separation and identification of various subunits and their role in eicosanoid biosynthesis. Methods: Purification of rat testicular GSTs by affinity chromatography, employing S-hexylglutathione-linked epoxy-activated Sepharose 6B column and separation of individual subunits by reverse phase-high pressure liquid chromatography (RP-HPLC). Characterization of affinity purified GSTs by Sodium dodecyl sulfate-polyacrylamide gel electlophoresis (SDS-PAGE) and Western blot analysis. The role of testicular GSTs in eicosanoid biosynthesis was determined by incubating GSTs with 5,6-Leukotriene A4Me (LTA4Me) and prostaglandin H2(PGH2) and analyzing the products formed on HPLC/TLC. Results: The present study reveals that majority of rat testicular GSTs are of Yb size (60%) with molecular weight of 27kDa. The most predominant subunits, however, are GST Yn2(27%), followed by GST Yc(24%) and GST Ynl(20%). These testicular GSTs showed very high Leukotriene C4(LTC4) synthase activity with 5,6-Leukotriene A4Me(LTA4Me) as the substrate and prostaglandin D (PGD) synthase activity with prostaglandin H2(PGH2) as the substrate. Conclusion: Majority of rat testicular GSTs are Yb sized and are involved in the synthesis of eicosanoids like LTC4 and PGD2.(Asian J Androl 2000 Dec;2:277-282) | D.Anuradha K.VeeraReddy T.CharlesKumar S.Neeraja P.R.K.Reddy P.Reddanna | 2000 | Asian Journal of Andrology2000，2，4： | 1 |
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