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)

Guinea pig spermatozoa were found to contain a fully-latent cysteine proteinase that could be unmasked by incubating epididymal sperm for 2 hr at pH 3.5 and 37 degrees C. The proteinase was identified as cathepsin L (EC 3.4.22.15) on the basis of its optimal hydrolysis of benzyloxycarbonyl-Phe-Arg-7-(4-methyl)coumarylamide (Z-Phe-Arg-NMec) at pH 5.5; lack of action on Z-Arg-Arg-NMec and Arg-NMec; urea-enhanced digestion of azocasein; marked sensitivity to thiol reagents, leupeptin, Z-Phe-Phe-CHN2, and L-trans-epoxy-succinylleucylamido(3-methyl)butane (Ep-475 or E-64-c); and insensitivity to pepstatin and serine proteinase inhibitors. Gossypol, a male antifertility agent, was inhibitory. The unmasking phenomenon was reversibly inhibited by HgCl2 and mersalyl acid, and prevented by leupeptin and Ep-475, but not by pepstatin.
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PMID:Cathepsin L--a latent proteinase in guinea pig sperm. 334 13

The proteins which are secreted from the restricted part of the epididymis are suggested to sustain sperm maturation. In porcine species, as the potential abilities of sperm for movement and fertilization greatly increase in the corpus epididymis, the secretions in both the caput and corpus epididymis seem to be very important for the sperm maturation. In this study, we have directed our attention to the 40 kDa protein which is detected in the fluid of the distal caput epididymis of boar. It was purified from the porcine cauda epididymal fluid and its cDNA was cloned from the cDNA library of the distal caput epididymis. According to the deduced amino acid sequence, the 40 kDa protein has been identified as procathepsin L. Northern blot analysis showed that the procathepsin L mRNA was most abundant in the distal caput epididymis among the tissues as examined. Consistent with the distribution of the procathepsin L mRNA in the epididymis, the activity of procathepsin L was absent in the fluid of the proximal and mid caput epididymis and first appeared in the distal caput epididymal fluid, whose contents gradually decreased with the passage through the epididymis. These results first appeared in the first distal caput epididymis expresses very high levels of procathepsin L and unusually secretes it into the luminal fluid instead of targeting it to lysosomes. It has been also found that the mRNA of PDGF, which is known to enhance cathepsin L expression in the culture cells, is very high in the mid caput epididymis, which just precedes the site of procathepsin L secretion. This result indicates that PDGF directly regulates the locally restricted expression and secretion of procathepsin L in the epididymis, which is one of the possible mechanisms involved in the functional differentiation in the epididymis.
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PMID:Direct evidence for the elevated synthesis and secretion of procathepsin L in the distal caput epididymis of boar. 749 81

To examine the precise localization of lysosomal cysteine proteinases, cathepsins B, H, and L in rat epididymal epithelial cells, immunohistochemistry and enzyme assay were applied to the epididymal tissue. Granular immunodeposits for cathepsins B and H were detected in epididymal epithelial cells, whereas faint or no immunoreactivity for cathepsin L was found. Moreover, immunoreactivity for cathepsin B appeared mainly in principal cells and was more intense in the head of the epididymis than in the tail, whereas that for cathepsin H appeared in both principal and clear cells and was more intense in the tail than the head. By enzyme assay, activities of cathepsins B and H showed a similar distribution to that of the immunoreactivity. The cathepsin L-specific activity was distributed evenly in each part of the epididymis and was also detected in epididymal fluids obtained from the body and tail parts. By immunoblotting, proforms of cathepsins B, H, and L were present in the seminal fluid. The results suggest that cathepsins B and H are involved in the intracellular degradation system of epididymal epithelial cells, and proforms of cathepsins B, H, and L may be secreted into the epididymal duct lumen.
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PMID:Lysosomal cysteine proteinases in rat epididymis. 830 58