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

1. The procedure of Barrett [(1973) Biochem. J.131, 809-822] for isolating cathepsins B and D from human liver was modified for use with rat liver and skeletal muscle. The purified enzymes appeared to be similar to those reported in other species. 2. Sephadex G-75 chromatography of concentrated muscle extract resolved two peaks of cathepsin B inhibitory activity, corresponding to molecular weights of 12500 and 62000. 3. The degradation of purified myofibrillar proteins by cathepsins B and D was clearly demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. After incubation with enzyme, the polypeptide bands representing the substrates decreased in intensity and lower molecular weight products appeared. 4. Cathepsins B and D, purified from either rat liver or skeletal muscle, were shown to degrade myosin, purified from either rabbit or rat muscle. Soluble denatured myosin was degraded more extensively than insoluble native myosin. Degradation by cathepsin B was inhibited by lack of reducing agent, or by myoglobin, iodoacetic acid and leupeptin, but not by pepstatin. The same potential modifiers were applied to cathepsin D, and only pepstatin produced inhibition. 5. Rat liver cathepsin B had a pH optimum of 5.2 on native rabbit myosin. The pH optimum of cathepsin D was 4.0, with a shoulder of activity about 1pH unit above the optimum. 6. Rat liver cathepsins B and D were demonstrated to degrade rabbit F-actin at pH5.0, and were inhibited by leupeptin and pepstain, respectively. 7. The degradation of myosin and actin by cathepsin D was more extensive than that by cathepsin B.
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PMID:Degradation of myofibrillar proteins by cathepsins B and D. 2 66

Proteinase activity in the cellular slime mould Dictyostelium discoideum has been analyzed by electrophoresis on polyacrylamide gels containing denatured hemoglobin. At least eight bands due to acid proteinases have been defined using extracts of myxamoebae, four bands A-D which move faster than the fifth and major band E, a minor band E' which moves just behind E and two slow bands G and H. Fruiting body formation was accompanied by the appearance of one new proteinase band F. The proteinases were present in extracts of both axenically-grown and bacterially-grown cells. Differences between the pH dependence and stability of the individual proteinases were detected. Inhibitor studies suggested that the faster proteinases A-D may be cathepsin B-like, whilst the slower enzymes E, E' and F do not fit readily into any known group of proteinases since they were sensitive to HgCl2 but not to other inhibitors of cathepsin B and not to inhibitors of cathepsin D-like proteinases under standard conditions. None of the proteinases was apparently formed during or after preparation of extracts and the proteinases could be re-run on polyacrylamide gels to give only the band expected from the first run. The bands are believed to reflect multiple proteinase activities within the cell.
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PMID:Multiple acid proteinases in the cellular slime mould Dictyostelium discoideum. 3 40

Canine liver lysosomes were purified by sucrose discontinuous density gradient centrifugation and then ruptured by sonication to obtain the soluble fraction. This soluble lysosomal fraction, which contained a 25-fold increase in acid phosphatase activity per mg of total protein when compared with the original homogenate, was incubated with a subfraction (1.110 less than d less than 1.210 g/cm3, HDL3) of canine high density lipoproteins (HDL) at pH 3.8. HDL3 proteolysis by lysosomal proteases, measured as the release of peptides and amino acids by the ninhydrin reaction, followed hyperbolic curves with straight lines (r = 0.99) obtained on Lineweaver-Burk plots. Km calculated from the Lineweaver-Burk plot was 635 mug of HDL3 protein per 0.5 ml of incubation mixture. Optimum HDL3 proteolysis was observed from pH 3.8 to 4.5. Incubation with the other subcellular organelle fractions did not result in HDL3 proteolysis. To evaluate the effects of enzyme inhibitors, iodoacetate, p-chloromercuribenzoate (both specific for the endopeptidase, cathepsin B (EC 3.4.22.1)) and pepstatin (specific for the endopeptidase, cathepsin D (EC 3.4.23.5) were tested. Iodoacetate and p-chloromercuribenzoate inhibited HDL3 proteolysis 100% and bovine serum albumin proteolysis 65%. Pepstatin inhibited HDL3 proteolysis 45% and bovine serum albumin proteolysis 70%. The in vitro data presented support the hypothesis that hepatic lysosomes play an important role in HDL3 catabolism in the dog. Furthermore, results obtained from enzyme inhibition studies suggest that a specific lysosomal endopeptidase, cathepsin B, may play the key role in HDL3 proteolysis.
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PMID:Proteolysis of canine apolipoprotein by acid proteases in canine liver lysosomes. 17 45

Because protein degradation in liver and skeletal muscle is increased by thyroid hormones and decreased by thyroidectomy; we investigated the influence of thyroid hormones on the level of lysosomal enzymes. Hypophysectomized rats received daily injections of L-thyroxine or L-triiodothyronine. After 3 days of this regimen, homogenates of liver and skeletal muscle showed a 2- to 3-fold increase in the activities of cathepsin D, cathepsin B, and other lysosomal enzymes including leucine aminopeptidase, acid phosphatase, beta-galactosidase, N-acetylglucosaminidase, and alpha-mannosidase. In liver, this effect reflected increased enzyme activity in the two subcellular fractions that normally contain lysosomes. Titration of cathepsin D with pepstatin indicated that the increase in this activity resulted from an increase in the number of enzyme molecules. These effects occurred with both pharmacologic (thyrotoxic) and physiologic (growth-promoting) doses of thyroid hormones. Liver and skeletal muscle from thyroidectomized rats had approximately 50% of the normal levels of lysosomal enzyme activities. Under these various conditions, heart and kidney, tissues in which protein degradation does not appear to be influenced by thyroid hormones, showed no significant changes in lysosomal hydrolases. Thus, thyroid hormones regulate proteolytic and other lysosomal enzyme activities in those tissues in which these hormones influence protein degradation. Many characteristic features of hyperthyroidism and hypothyroidism may result from changes in levels of lysosomal enzymes.
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PMID:Thyroid hormones control lysosomal enzyme activities in liver and skeletal muscle. 27 25

In vitro degradation of insoluble vitreous collagen by the action of collagenolytic cathepsin was studied biochemically. Among bovine ocular tissues, the uvea and the retina showed relatively high collagenolytic activity. The ciliary body revealed the highest specific activities of both cathepsin B and collagenolytic cathepsin. Leupeptin and p-chloromercuribenzoate inhibited both cathepsin B and collagenolytic cathepsin in the ciliary body lysosomes. Pepstatin inhibited cathepsin D, but did not affect cathepsin B and collagenolytic cathepsin. It is suggested that distribution and properties of collagenolytic cathepsin are similar to those of cathepsin B in the bovine eye.
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PMID:The distribution and some properties of collagenolytic cathepsin in the bovine eye. 30 80

The activity of cathepsin B was assayed in murine resident peritoneal macrophages, and after stimulation of the cells in vivo and in vitro. The resident cells showed a very low activity of the enzyme, compared to the activities of three other lysosomal enzymes: cathepsin D, acid phosphatase, and beta-glucuronidase which were tested simultaneously. Endocytosis of carrageenan, latex, or carbon particles in vitro induced a prominent rise in intracellular cathepsin B activity. Addition of endotoxin from Escherichia coli in vivo or in vitro, or cell wall products from streptococci in vitro caused no change in cathepsin B activity. There was a release of enzyme activity to the medium after a 72-hour culture of macrophages. However, the release, calculated as a percentage of total activity, was not influenced by any treatments mentioned. All significant rises in enzyme activity could be inhibited by the addition of cycloheximide, and it was concluded that increased enzyme activity was dependent on new protein synthesis.
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PMID:Cathepsin B activity in stimulated mouse peritoneal macrophages. 38 72

Individual aggregates, migrating pseudoplasmodia, and sorocarps of Dictyostelium discoideum were assayed for proteolytic activities by colorimetric and fluorometric techniques. Cathepsin D-like and cathepsin B-like acid protease activities were found to decrease throughout development, but the patterns of decrease were different for the two enzymes. A gradual decrease was found for cathepsin D, whereas a sharp decrease between aggregates and migrating pseudoplasmodia was detected for cathepsin B. By using microdissection techniques and fluorometric assays for amino acids and peptides, prestalk cells and prespore cells exhibited no difference in cathepsin D activity, whereas cathepsin B activity was higher in the prestalk cells. Similarly, stalk cells and spores in the sorocarps showed no difference in cathepsin D activity, but showed a fivefold higher cathepsin B activity in the stalk cells. This finding suggests a possible role for cathepsin B in stalk cell differentiation.
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PMID:Protease activity during cell differentiation of the cellular slime mold Dictyostelium discoideum. 56 65

1. Proteoglycan was obtained from bovine nasal cartilage by a procedure involving sequential extraction with a low-ionic-strength KCl solution, then a high-ionic-strength CaCl2 solution. Purification was by CsCl-density-gradient centrifugation. 2. The CaCl2- extracted proteoglycan was subjected to proteolytic degradation by papain, trypsin, cathepsin D, cathepsin B, lysosomal elastase or cathepsin G. Degradation was allowed to proceed until no further decrease in viscosity was detectable. 3. The size and chemical composition of the final degradation products varied with the different proteinases. Cathepsin D and cathepsin G produced glycosaminoglycan-peptides of largest average size, and papain produced the smallest product. 4. The KCl-extracted proteoglycan was intermediate in molecular size and composition between the CaCl2-extracted proteoglycan and the largest final degradation products, and may have been formed by limited proteolysis during the extraction procedure. 5. It is postulated that the glycosaminoglycan chains are arranged in groups along the proteoglycan core protein. Proteolytic cleavage between the groups may be common to the majority of proteinases, whereas clevage within the groups is dependent on the specificity of each individual proteinase.
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PMID:The degradation of cartilage proteoglycans by tissue proteinases. Proteoglycan structure and its susceptibility to proteolysis. 60 25

1. CaCl2-extracted proteoglycan from bovine nasal cartilage was degraded by four tissue proteinases till no further decrease in hydroynamic size was obtained. The proteoglycan and its final degradation products were then fractionated by Sepharose 2B chromatography. 2. The average size of the degradation products was least for cathepsin B and lysosomal elastase, and greatest for cathepsin D and cathepsin G. The latter two proteinases also produced degradation products that showed the widest range of sizes. 3. The structure of the degradation products ranged from peptides containing a single glycosaminoglycan chain to those containing twelve or more chains. Of the four proteinases, only cathepsin B produced peptides that contained a single chondroitin sulphate chain. 4. The proteoglycan was very heterogeneous with respect to size and chemical composition. Its behaviour on electrophoresis suggested that at least two genetically distinct core proteins might exist. 5. Irrespective of their structural variations, all proteoglycan molecules were able to interact with hyaluronic acid. In contrast, none of the degradation products were capable of this type of interaction. 6. A pathway for the proteolytic degradation of proteoglycans is postulated in which the sites of initial cleavage may be common to the majority of proteinases, whereas the production of the final clusters is dependent on the specificity of the proteinase. Only those proteinases of broadest specificity can produce single-chain chondroitin sulphate-peptides.
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PMID:The degradation of cartilage proteoglycans by tissue proteinases. Proteoglycan heterogeneity and the pathway of proteolytic degradation. 60 26

In the last 11 years the authors have succeeded in isolating nearly 40 enzyme inhibitors of small molecular size from microbial origins. These inhibitors proved to be not only useful tools in analyses of homeostasis of living organisms but also promising agents for cancer chemotherapy. Leupeptin was originally isolated as an inhibitor against serine or thiol proteases such as trypsin, plasmin, papain and cathepsin B. And soon it was demonstrated that leupeptin suppressed chemical carcinogenesis in rats. Pepstatin has an extremely strong activity to inhibit pepsin and cathepsin D. It also inhibits ascites accumulation caused by neoplastic diseases. Bestatin is a specific inhibitor against aminopeptidase B and leucine aminopeptidase. The enzymes are located on the surface membrane in various kinds of cells including lymphocytes. Bestatin was shown to enhance not only blastogenesis of lymphocytes in vitro but also establishment of delayed-type hypersensitivity in vivo. Combined use of bestatin and other antitumor agents gave promising results in animal experiments. Studies on enzyme inhibitors have provided us a new approach to cancer chemotherapy.
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PMID:Enzyme inhibitors in relation to cancer therapy. 61 3


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