Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The partial purification of two intracellular proteinases from the protozoan parasite Entamoeba histolytica is reported. One of these enzymes is an acid proteinase exhibiting maximum activity at pH 3.5 (hemoglobin substrate), is little affected by a range of inhibitors or activators, and is presumed to be similar to cathepsin D. Also present is a neutral proteinase exhibiting optimum activity at pH 6.0 (azocasein) but only poorly hydrolyzing either hemoglobin or serum albumen. This latter enzyme displayed no metal ion requirement, but was markedly inhibited by thiol-blocking agents and activated by free sulhydryl-containing compounds.
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PMID:Partial purification and some properties of a neutral sulfhydryl and an acid proteinase from Entamoeba histolytica. 1 91

A neutral proteinase secreted by rabbit synovial fibroblasts in parallel with specific collagenase was partially purified by ion-exchange chromatography. At pH 7.6 this proteinase degraded 35S-labelled bovine nasal proteoglycan and azo-casein. The enzymic activity was inhibited by EDTA, 1,10-phenanthroline and serum, whereas di-isopropyl phosphorofluoridate and soya-bean trypsin inhibitor had little effect. By gel filtration the apparent mol.wt. of the enzyme was 25000. The fibroblast neutral proteinase was compared with the proteoglycan-degrading neutral proteinases of rabbit polymorphonuclear-leucocyte granules. Two distinct activities were found in the granules: one was inhibited by soya-bean trypsin inhibitor and the other by EDTA. The proteoglycan-degrading proteinases of rabbit fibroblasts and polymorphonuclear leucocytes at acid pH also were examined. Both cathepsin D and a thiol-dependent proteinase contributed to the degradation of proteoglycan at pH 4.5.
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PMID:Proteoglycan-degrading enzymes of rabbit fibroblasts and granulocytes. 3 Apr 51

Acid and neutral proteinases were isolated with the purpose of investigating their participation in the breakdown of hypothalamic peptides and proteins. The acid proteinase was purified about 1000-fold from hypothalamus by precipitation with acetone, chromatography on SP-Sephadex G-50, gel filtration through column of G-100 and chromatography on DEAE-Sephadex A-50. The molecular weight of the enzyme was approximately 50.000. Maximal activity against hemoglobin was obtained at pH 3,2--3,5: serum albumin was split much more slowly. Hypothalamus acid proteinase was partially inhibited by beta-phenyl pyruvate, benzothonium cloride, and was completely inhibited by low concentrations of pepstatin. This proteinase splits somatostatin, Substance P and some C-fragments of Substance P. The probable sites of enzyme action on these peptides were determined by the end group dansyl technique. Neutral proteinase was isolated from the supernatant fraction(100.000 g) of a 0,3 M sucrose homogenate of bovine hypothalamus by chromatography on DEAE Sephadex A-50, gel filtration through Sephadex G-100 and rechromatography on DEAE sephadex A-50 using luliberin as substrate. The rates of breakdown of luliberin and denaturated hemoglobin were measured by fluorometric estimation of acid-soluble peptides wieht o-phthaldialdehyde. The purifed enzyme preparations have a pH optimum of activity at 7--7,5. The enzymes molecular weight was approximatelyy 30--40.000. Enzyme activity was inhibited by L-1-tosylamide-2-phenylethylchloromethyl ketone, p-chloromercuribenzoate and divalent ions Co2+, Zn2+ and was significantly enhanced by dithiothreitol. The Km values for the reaction of hydrolysis of luliberin and hemoglobin were 1,33.10(-5) and 5,2.10(-5) M respectively. The neutral proteinase from the hypothalamus cleaves luliberin, somatostatin and Substance P. Sites of action of the enzyme upon those peptides were determined by means of the dansyl technique. The acid proteinase, most likely cathepsin D, and neutral proteinase from hypothalamus, may play an important role in the formation and breakdown of peptide hormones in the hypothalamus.
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PMID:[Breakdown of luliberin, somatostatin and substance P as an effect of hypothalamic endopeptidases]. 4 63

Patients with the DMC syndrome have been suggested to possess a specific sulfatase abnormality and/or to be deficient in a proteinase cleaving glycoprotein-acid mucopolysaccharide (AMP) linkage. We have previously found in DMC patients an abnormal excretion of urinary AMPs of which hyaluronic acid and chondroitin sulfate (A + C) were oversulfated and keratosulfate and heparan sulfate were undersulfated. Lysosomal acid proteinase, i.e. cathepsin D (EC 3.4.23.5) and neutral proteinase : elastase (EC 3.4.21.11) and cathepsin G were found to be normal in DMC patients. However, alpha 2-macroglobulin in serum was raised. This increase may be associated with a complex formation of alpha 2-macroglobulin with a neutral proteinase released from the cells. Increased levels of chondroitin sulfate N-acetylgalactosamine-6-sulfate sulfatase and sulfamidase and decreased enzymic levels of arylsulfatase A and B (EC 3.1.6.1) were found in leucocytes of DMC patients. The sulfatase activities assayed in the present study support our theory that a specific sulfatase abnormality may exist in the DMC syndrome.
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PMID:Lysosomal (leucocyte) proteinase and sulfatase levels in Dyggve-Melchior-Clausen (DMC) syndrome. 7 86

A possible mechanism for tumor cell invasion of normal tissue might be secretion of proteolytic enzymes. This study compares and contrasts production and secretion of proteinases by cell cultures of normal and chemically transformed mouse epithelial cells. Lysates of normal and neoplastic cells contain similar amounts of neutral proteinase, cathepsin D and plasminogen activator. Neither collagenase nor elastase could be identified in lysates of, or serum-free culture medium bathing, normal or neoplastic cells. Neoplastic cells secrete ten times more plasminogen activator than normal cells. Our data support the hypothesis that plasminogen activator produced by neoplastic cells could fuction to activate latent proteolytic enzymes secreted by connective tissue cells which might result in spread of neoplastic cells into normal tissue.
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PMID:Production and secretion of proteolytic enzymes by normal and neoplastic cells. 45 22

The Dyggve-Melchior-Clausen (DMC) syndrome includes short stature, dwarfism, mental retardation, and skeletal abnormalities especially in the spine and the extremities resembling the findings in the mucopolysaccharidoses. A particular abnormality is the "lace border" found on radiological examination of the iliac crest. The three original cases have been followed for 15--20 years and the course is characterized by increasing mental retardation and motor disability whereas the "lace border" is less pronounced than before. A survey of 17 other cases is given and similarities and differencies to the mucopolysaccharidoses are pointed out. Patients with the DMC syndrome have been suggested to be deficient in an enzyme cleaving glycoprotein-acid mucopolysaccharide (AMP) linkage. We have previously found in DMC patients, an abnormal excretion of urinary AMP's of which some were undersulfated and some were oversulfated. Lysosomal acid proteinase, i.e., cathepsin D and neutral proteinases: elastase and cathepsin G were found to be normal in DMC patients. However, alfa2-macroglobulin in serum was raised. This increase may cause an inhibition of the neutral proteinases. An increased level of chondroitin sulfate N-acetylgalactosamine-6-sulfate-sulfatase and decreased enzymic levels of aryl sulphatase A and B (assayed with p-nitrocatecholsulfate as a substrate) were found in leucocytes of DMC patients. Metabolic studies have revealed an unbalanced incorporation of glycoprotein AMP-precursors in DMC lymphocytes. All in all the data suggests the DMC syndrome to be an inborn error of glycoprotein-AMP-metabolism.
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PMID:The Dyggve-Melchior-Clausen (DMC) syndrome. A 15 year follow-up and a survey of the present clinical and chemical findings. 57 40

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

1. Human polymorphonuclear leucocyte elastase and cathepsin G were incubated with preparations of isolated human glomerular basement membrane at neutral pH and 37 degrees C. 2. The ability of these enzymes to degrade glomerular basement membrane was followed by the release of hydroxyproline. Both proteinases released considerable amounts of hydroxyproline. 3. By using Sephadex G-100 it was shown that the solubilized basement membrane fragments appeared as a single peak and had a molecular weight of over 100 000. These proteins after reduction were analysed by sodium dodecyl sulphate-gel electrophoresis to examine their subunit pattern and determine their molecular size. 4. The released basement membrane proteins gave at least four precipitin lines with a rabbit anti-(glomerular basement membrane) antiserum. 5. These results support the concept that polymorphonuclear leucocyte neutral proteinases play an important role in the pathogenesis of glomerulonephritis. 6. At acid pH values cathepsin B also released hydroxyproline from human glomerular basement membrane but the lysosomal carboxyl proteinase, cathepsin D, had no action.
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PMID:The degradation of human glomerular basement membrane with purified lysosomal proteinases: evidence for the pathogenic role of the polymorphonuclear leucocyte in glomerulonephritis. 63 Aug

In continuation of previous studies, which showed a catabolic defect in proteoglycan metabolism, enzymes which degrade the proteoglycan macromolecules, e.g. proteinases (cathepsin D, elastase, and cathepsin G) and glycoisidases (arabinosidase and xylosidase) have been assayed in leucocytes of DMC patients. The regulator of lysosomal proteinases, cyclic AMP and serum antiproteinases, e.g. alpha1-AT and alpha2-M, have also been assayed. The proteinases assayed were normal in DMC patients. Arabinosidase activity in leucocytes of the patients was found to be decreased three fold, while xylosidase activity was increased three fold. A four-fold increased concentration of cyclic AMP in leucocytes of the patients and an increased serum concentration of alpha2-M associated with its abnormal pattern in crossed immunoelectrophoresis have been found. The abnormality in serum alpha2-M of DMC patients may be explained by a complex formation of alpha2-M with collagenase released from the lysosomes. Finally, an abnormal peptidoglycan has been demonstrated in DMC urine.
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PMID:Biochemical abnormalities in Dyggve-Melchior-Clausen syndrome. 63 1


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