Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An apparently specific glutathione oxidase activity is present in renal cortex, epididymal caput, jejunal villus tip cells, choroid plexus, and retina (but not in liver). The activity is membrane-bound and is localized on the luminal surface of the brush border membranes of the kidney and jejunum. The distribution and localization of the oxidase are similar to those of gamma-glutamyl transpeptidase, suggesting that there is a significant relationship among the translocation of intracellular glutathione, the extracellular oxidation of glutathione to glutathione disulfide, and the reactions of the gamma-glutamyl cycle. Thus, both glutathione present in the blood plasma and intracellular glutathione translocated to the cell surface are accessible to oxidation and transpeptidation. Acceptor substrates of the transpeptidase (e.g., L amino acids) promote transpeptidation and decrease oxidation of glutathione. Conversion of glutathione to glutathione disulfide is followed by utilization of the latter compound by gamma-glutamyl transpeptidase and dipeptidase. Although intracellular oxidation of glutathione to glutathione disulfide is readily reversed by the action of glutathione reductase, glutathione disulfide formed extracellularly cannot be reduced; instead, it undergoes hydrolytic and transpeptidation reactions leading to gamma-glutamyl amino acid and amino acid products which may be recovered by being transported into the cell.
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PMID:Conversion of glutathione to glutathione disulfide by cell membrane-bound oxidase activity. 3 3

The angiotensin-converting enzyme (ACE) plays a crucial role in male fertilization and is a key regulator of blood pressure. Testicular ACE (tACE), the germinal specific isozyme expressed on different promoters, exclusively carries out the role of ACE in fertility, although the site and mode of action are not well known. To investigate the contribution of tACE in fertilization, we produced transgenic mouse lines carrying a dipeptidase-inactivated mutant. Although the transgenic mice showed normal blood pressure, kidney morphology, and fertility, reduced fertilization was observed after in vitro fertilization (IVF). The sperm-zona pellucida (ZP) binding was exclusively impaired in these lines in a manner similar to that observed in an Ace knockout mouse. The dipeptidase activity was reduced in epididymal ingredients but not in the testis. Furthermore, direct application of mutant protein did not suppress sperm-ZP binding of intact sperm during IVF, implying that the dipeptidase-inactivated mutant affects sperm modification in the epididymis for ZP binding. Our results indicate that the dipeptidase-inactivated tACE acts in vivo, suggesting that tACE contributes to fertilization as a dipeptidase at least in the epididymis.
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PMID:Dipeptidase-inactivated tACE action in vivo: selective inhibition of sperm-zona pellucida binding in the mouse. 1763 45