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 reliability of enzyme histochemical semipermeable membrane techniques for the demonstration of acid hydrolases was investigated with a combined histochemical and biochemical study. In part 1 the histochemical findings were presented. In this communication the biochemical findings are reported and compared with the histochemical findings. In m. soleus, m. plantaris, m. gastrocnemius and diaphragm of vitamin E deficient rabbits the activity of the lysosomal acid hydrolases, cathepsin D, acid maltase, acid phosphatase and beta-glucuronidase is significantly increased. This increase in activity of the investigated acid hydrolases was equal for muscles with an aerobic or an anaerobic metabolism. By means of statistical calculations the activity of the enzymes demonstrated with histochemical techniques was compared with the enzyme activity determined with biochemical techniques. From the results of this investigation it can be concluded that the histochemical semipermeable membrane techniques for the demonstration of activity of acid hydrolases are very reliable. Considering the fact that these techniques are also tissue-saving, they are therefore extremely suitable for the study of catabolic wasting processes in skeletal muscle tissues of patients with inherited or acquired muscular diseases.
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PMID:Evaluation of histochemical observations of activity of acid hydrolases obtained with semipermeable membrane techniques: a combined histochemical and biochemical investigation 2. The biochemical investigation and comparison with the histochemical observations. 35 51

The reliability of enzyme histochemical observations of activities of acid hydrolases was investigated with a combined histochemical and biochemical study. Specimens of m. soleus, m. plantaris, m. gastrocnemius and diaphragm of normal and of vitamin E deficient rabbits were used. For the histochemical investigation, activity and localization of acid phosphatase, beta-glucuronidase, leucine aminopeptidase and E600 resistant non-specific arylesterase were examined with semipermeable membrane techniques. For the biochemical investigation, activity of acid phosphatase, beta-glucuronidase, cathepsin D, acid maltase and neutral maltase was determined. By means of stastical calculations the enzyme activities demonstrated with histochemical techniques were compared with the enzyme activities determined with biochemical techniques. In the present communication the histochemical findings are reported and discussed. From the histochemical findings it appeared that activity of the acid hydrolases investigated is strongly increased in both a granular and a diffuse pattern in skeletal muscle of vitamin E deficient rabbits. The statistical calculations of the histochemical findings clearly reveal that the increased activity of one acid hydrolase was highly significantly paralleled by an increased activity of a second acid hydrolase. Moreover the probability that the activity of all other histochemically studied acid hydrolases was significantly increased was rather high. The increase in activity of the acid hydrolases studied was the same in muscles with an aerobic or an anaerobic metabolism. Moreover there was no difference in activity and localization of the acid hydrolases in aerobic type I and anaerobic type II fibres. The localization of acid phosphatase and beta-glucuronidase activity muscle fibres mostly coincided. In cases where these enzymes were localized both centrally and in the subsarcolemnal areas of the muscle fibres, the activity of E600 resistant naphtholesterase was usually, and the activity of leucine aminopeptidase was exclusively located in the subsarcolemnal areas. All of the examined acid hydrolases were found to be present in the inflammatory exudate and in the connective tissue.
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PMID:Evaluation of histochemical observations of activity of acid hydrolases obtained with semipermeable membrane techniques: a combined histochemical and biochemical investigation 1. The histochemical investigation. 35 53

A rabbit model was used to determine the effects of prostaglandins and arachidonic acid on cellular integrity and survival during endotoxic shock. Prostaglandins A2, E1 and F2alpha were infused intravenously at a rate of 1.0 microgram/kg/min for 105 min beginning 15 min after the administration of an LD60 dose of Escherichia coli endotoxin. While each of the prostaglandins tested significantly attenuated the accumulation of lactic acid dehydrogenase in the plasma of shocked animals, none were able to protect against the increase in the plasma activities of glutamic pyruvic transaminase or cathepsin D during the shock state. Prostaglandins A2, E1 and F2alpha did not significantly enhance the survival of the treated animals as compared to vehicle-treated controls. In contrast, arachidonic acid 15 microgram/kg/min i.v.) significantly prevented the accumulation of lactic acid dehydrogenase and glutamic-pyruvic transaminase activities in the plasma of shocked animals, and also significantly increased the number of survivors in this group 48 hours after the endotoxin administration. In summary, while the treatment of endotoxic rabbits with prostaglandins of the A, E and F series was of no survival value, the treatment of these animals with a substrate of the prostaglandin synthetase complex resulted in a dramatic increase in the survival rate. The mechanism of action of arachidonic acid in this regard is not clear.
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PMID:Endotoxic shock in the rabbit: the effects of prostaglandin and arachidonic acid administration. 35 77

Inactive human renin is found in amniotic fluid, plasma, and kidney and may be a renin precursor ("prorenin"). The mechanism of activation of inactive renin in vivo is not known. The present study examined the hypothesis that cathepsin D, a lysosomal pepsin-like endopeptidase may be capable of eliciting activation. Cathepsin D was incubated with inactive renin in human amniotic fluid at pH 4.8 and 22 C for 0-5 h. Marked activation occurred and the reaction displayed first order kinetics with respect to the concentration of cathepsin D. The initial velocity of conversion of inactive renin to active renin by cathepsin D was 0.007%/min/microgram cathepsin D. Under identical conditions, the initial velocity of conversion by pepsin was 0.18%/min/microgram pepsin. The 25-fold higher potency of pepsin compared with cathepsin D is in accordance with the recognized relative substrate affinities and catalytic efficiencies of the two enzymes. Inactive renin in human amniotic fluid seems to be similar to that found in human kidney and since cathepsin D is present in juxtaglomerular cells, this activation process may have physiological importance.
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PMID:Activation of human inactive ("pro-") renin by cathepsin D and pepsin. 37 40

Prostacyclin (PGI2) infused at a rate of 350 ng/kg/min significantly increased survival time in rats subjected to Noble-Collip drug trauma from 2.7 +/- 0.3 to 4.6 +/- 0.2 h (p less than 0.01) compared with traumatized rats given only the vehicle (Tris buffer). Moreover, PGI2 treated rats exhibited significantly lower circulating cathepsin D and myocardial depressant factor (MDF) activities, indicative of lower lysosomal disruption and lower toxic factor formation. PGI2 induced vasodilation in rats as well as these other protective effects.
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PMID:Beneficial actions of prostacyclin in traumatic shock. 38 29

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

A model for the structure and function of extracellular carboxyl (acid) proteases can be established from three amino acid sequences and four crystal structures of these enzymes. The carboxyl proteases from gastric and fungal origins are very homologous in both primary and tertiary structures. The molecules consist of about 320 residues organized with a secondary structure which is primarily comprised of beta-strands and very similar tertiary structures. An apparent binding cleft, which can accommodate a substrate with about eight amino acid residues, contains near its midpoint the active center residues Asp-215, Asp-32, and Ser-35. These three residues are hydrogen bonded to each other. An intracellular carboxyl protease, cathepsin D, is very homologous to the extracellular enzymes in N-terminal amino acid sequence and primary structure location of active center residues. The tertiary structure of cathepsin D is probably similar, as well. However, cathepsin D contains a unique hydrophobic "tail" made up of about 100 residues added on the C-terminal side. Cathepsin D precursor is over 100,000 daltons in molecular weights, as contrasted to the gastric carboxyl protease zymogens, which are about 40,000 daltons. Carboxyl proteases contain two lobes symmetrical in peptide chain conformations. Each of the lobes also consists of two homologous structural units. These structural characteristics suggest that the original gene was coded for only about eighty amino acid residues and that gene duplication and fusion has taken place twice to produce a single chain carboxyl protease with four basic structural units in two symmetrical lobes. The formation of the zymogens and the cathepsin D "tail" must have resulted from various gene fusions. Partial sequence comparisons also suggest that cathepsin D may be an evolutionary ancestral chain for gastric carboxyl proteases.
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PMID:Evolution in the structure and function of carboxyl proteases. 38 85

Morphology, lysosomal enzyme activities, and phagocytosis via immunological receptors were tested in peritoneal macrophages from germfree and conventional mice. Nonstimulated macrophages from germfree mice showed less spreading and were more easily detached when seeded on glass than conventional macrophages. The activities of the lysosomal acid phosphatase and cathepsin D were similar in the two cell groups, whereas beta-glucuronidase showed higher activity in macrophages from germfree mice. F(c) receptor-mediated phagocytosis of opsonized sheep erythrocytes was equally effective in germfree and conventional macrophages, and both cell types attached but did not internalize erythrocytes via the C(3)b receptor. Intraperitoneal injections of mineral oil caused a significantly higher influx of macrophages in conventional mice than in germfree mice, whereas the influx of polymorphonuclear cells was enhanced in both animals. Stimulation in vivo with oil or Escherichia coli endotoxin increased cell size, spreading ability, membrane ruffling, and lysosomal enzyme activities in macrophages from both conventional and germfree mice. The Fc-mediated phagocytosis was not influenced by stimulation, whereas the capacity to internalize via C(3)b receptor was triggered in macrophages from conventional mice, but not in corresponding cells from germfree mice. Similar results were obtained after stimulation with endotoxin in vitro. Culture in fetal calf serum for 72 h caused intracellular rises in all three enzyme activities tested in macrophages from conventional mice, whereas only the activity of acid phosphatase was increased in macrophages from germfree mice. Stimulation with zymosan in vitro caused selective release of lysosomal enzyme activity in macrophages from both animal groups. We conclude that peritoneal macrophages from germfree mice share several properties with cells from conventional mice, however, unstimulated beta-glucuronidase activity was increased, whereas spreading on glass, chemotactic response, in vitro induction of lysosomal enzymes, and the capacity to internalize via the C(3)b receptor after stimulation were reduced or absent.
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PMID:Comparison of peritoneal macrophages from germfree and conventional mice. 39 29

The rate of of protein degradation in muscle changes in many states but the nature of these changes is often paradoxical. Thus there can be increases during growth (anabolic increases) as well as during wasting (catabolic increases). Decreases can occur during growth (anabolic decreases) as well as during wasting (catabolic decreases). These changes are observed in man (as judged by changes in 3-methylhistidine excretion) and in experimental animals. The nature of the changes is not understood but it is possible that muscle growth induces increased degradation as part of the accompanying myofibre remodelling. The rate of protein degradation can also be influenced by thyroid status, since in thyroid deficiency degradation is reduced and can be stimulated by triiodothyronine. This response is independent of changes in muscle growth. Finally, acute exercise suppresses protein degradation in vivo in man as well as suppressing protein synthesis (in vivo in rats). When protein degradation rates change, acid proteinase activities also change in muscle. The anabolic increase in degradation appears to involve increases in mainly cathepsin D whereas catabolic increases in degradation are associated with an increase mainly in pepstatin-insensitive acid autolytic activity.
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PMID:Protein degradation and the regulation of protein balance in muscle. 39 93

Cathepsin D was originally known simply as 'cathepsin' and was first purified in the late 1930s. Nowadays the enzyme is purified by conventional column chromatography, and by isoelectric focusing (which resolves isoforms), but affinity chromatography with pepstatin--Sepharose is also important. Cathepsin D is a glycoprotein of about 42,000 molecular weight; sometimes it comprises a single polypeptide chain but often this is found to have been 'nicked' about two-thirds of the way from one end. Cathepsin D is an 'aspartic proteinase' and may be one of the more primitive members of the family. The activity of cathepsin D is expressed exclusively at acidic pH values and the specificity shows a strong preference for cleavage near hydrophobic amino acids. Specific inhibition of cathepsin D with antibodies and pepstatin has provided strong evidence that the enzyme plays a part in intralysosomal proteolysis but there is as yet little evidence for extracellular activity.
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PMID:Cathepsin D: the lysosomal aspartic proteinase. 39 96


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