Open AccessNovel functional association of rat testicular membrane‐associated cytosolic glutathione S transferases and cyclooxygenase in vitro
Author(s) -
Neeraja S.,
Ramakrishna B.,
Sreenath A. S.,
Reddy G. V.,
Reddy P. R. K.,
Reddanna P.
Publication year - 2005
Publication title -
asian journal of andrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.701
H-Index - 74
eISSN - 1745-7262
pISSN - 1008-682X
DOI - 10.1111/j.1745-7262.2005.00030.x
Subject(s) - glutathione , arachidonic acid , cytosol , cyclooxygenase , prostaglandin e2 , prostaglandin , biochemistry , in vitro , glutathione s transferase , isozyme , enzyme , chemistry , biology , endocrinology
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 25‐28 kDa. In a coupled assay involving GSTs, arachidonic acid and cyclooxygenase‐1, rat testicular macGSTs produced prostaglandin E 2 and F 2α , while the cGSTs caused the generation of prostaglandin D 2 , E 2 and F 2α . 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.