Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human plasma fibronectin (pFN) contains a cryptic metalloprotease present in the collagen-binding domain. The enzyme could be generated and activated in the presence of Ca2+ from the purified 70-kDa pFN fragment produced by cathepsin D digestion. In this work we cloned and expressed the metalloprotease, designated FN type IV collagenase (FnColA), and a truncated variant (FnColB) in E. coli. The recombinant pFN protein fragment was isolated from inclusion bodies, and subjected to folding and autocatalytic degradation in the presence of Ca2+, and yielded an active enzyme capable of digesting gelatin, helical type II and type IV collagen, alpha- and beta-casein, insulin b-chain, and a synthetic Mca-peptide. In contrast, isolated plasma fibronectin, type I collagen, and the DNP-peptide were no substrates. Both catalytically active recombinant pFN fragments were efficiently inhibited by EDTA, and batimastat, and, in contrast to the glycosylated enzyme isolated from plasma fibronectin, were also inhibited by TIMP-2.
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PMID:The proteolytic activity of the recombinant cryptic human fibronectin type IV collagenase from E. coli expression. 1130 53

Erythropoietin (Epo) and the epo-receptor (EpoR) have been implicated in tumor growth, invasion and metastasis. We previously demonstrated Epo and EpoR expression in a small group of archived papillary thyroid cancers (PTC), but were unable to examine functional integrity using formalin-fixed tissues. In the present study, we examined the in vitro expression, induction and function of Epo and EpoR in papillary (NPA), follicular (WRO) and anaplastic (ARO-81) thyroid cancer cells. We found that all three cell lines expressed Epo and EpoR mRNA and that the hypoxia-mimetic cobalt induced Epo expression in all cell lines. None of the growth factors we examined (thyrotropin, vascular endothelial growth factor, IGF-I, or human Epo) altered Epo or EpoR gene expression. Importantly, however, administration of Epo to NPA but not WRO cells resulted in significant alterations in the expression of several mitogenic genes including cyclooxygenase-2 (COX-2), beta-casein (CSN2), wild type p53-induced gene-1 (WIG1) and cathepsin D (CTSD). Epo treated ARO-81 cells only had an increase in CSN2 expression. We conclude that Epo and EpoR are expressed by thyroid cancers and that stimulation of the Epo/EpoR signal pathway results in changes that could impact on the clinical behavior of thyroid cancers.
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PMID:Erythropoietin in thyroid cancer. 1669 98

Five different milk proteins (alpha-casein, beta-casein, kappa-casein, beta-lactoglobulin, and lactoferrin) and a peptide substrate were applied as substrates for the investigation of how lactosylation affected proteolysis by different proteases. After a lactosylation period of 4 days in aqueous solution, at 65 degrees C and pH 6.8 in a protein: lactose ratio of 1000 the proteins were enzymatically hydrolyzed by the three milk relevant proteases plasmin, cathepsin D, and chymosin. Lactosylation of all substrates affected hydrolysis by plasmin negatively, with the largest effect on the globular proteins. This could be explained by modification of lysine residues, being the preferred cleavage site for plasmin, but also the residue generally preferred for lactosylation. Lactosylation of the caseins and of beta-lactoglobulin did not affect subsequent cleavage by cathepsin D and chymosin significantly, but for beta-lactoglobulin, both the secondary as well as the tertiary structure were affected by lactosylation. In contrast, decreased hydrolysis by cathepsin D and chymosin was observed for lactoferrin after lactosylation. Decreased hydrolysis may be caused by a more compact tertiary structure induced by lactosylation of lactoferrin, as indicated by fluorescence spectroscopy measurements.
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PMID:Proteolysis of milk proteins lactosylated in model systems. 1735 84