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)

The inhibitory effect of thermo- and acid-resistant inhibitor of trypsin, chymotrypsin and leukocyte proteinases (TASPI) from rabbit serum on the kininogenase activity of cathepsins D from different organs and tissues (human spleen and liver, chicken liver, spleen leukemic infiltrate from patients with myeloid leukemia) was revealed. The progressive mechanism of TASPI and cathepsins D complexation dependent on time and temperature was revealed. The rate constant of inhibition (ki) of chicken liver cathepsin D by TASPI at 37 degrees was 4,25.10(3)M-1 min-1. It was shown that the kininogenase activity of chicken liver cathepsin D was slightly inhibited by the basic pancreatic trypsin and kallikrein inhibitor from bovine organs (Kunitz type) and by soya bean trypsin inhibitor. The role of TASPI as regulator of cathepsins D activity under pathological conditions accompanied by lysosomal disintegration is discussed.
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PMID:[Inhibition of kininogenase activity of cathepsins D by acid-resistant proteinase inhibitor from rabbit serum]. 691 92

Inactive renin (prorenin) can be activated by certain proteases in human blood, of which a possible source in vivo is polymorphonuclear leukocytes (PMNs). We extracted enzyme from PMNs using methods established for the recovery of neutral and acid protease fractions, and tested their effectiveness on plasma prorenin in vitro. Neutral protease preparations, possessing mainly chymotrypsin and elastase activity, produce no activation of prorenin. Exogenous pancreatic alpha-chymotrypsin does activate plasma prorenin, but less effectively than trypsin. From the quantity of PMNs extracted for neutral protease, and its failure to activate protenin, we deduce that this enzyme preparation, like exogenous chymotrypsin, is qualitatively unimportant. In contrast, the extracted PMN acid protease fraction, believed to be rich in cathepsin D, exhibited high prorenin activating ability, suggesting both quantitative and qualitative importance. The low pH requirement of this acid protease (near pH 4.0), together with its inactivity at neutral pH, argues against an important systemic role in the conversion of prorenin. However, it may contribute to systemic activation in partnership with other enzymes, or else play a specialized local role in situations where PMN concentration and activity increase, and the pH is on the acid side.
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PMID:Activation of prorenin by proteases from polymorphonuclear leukocytes. 699 62

Two trypsin inhibitor types, PII and PI II, were isolated by affinity chromatography of a potato extract on a column of trypsin immobilized on Sepharose 4B. Fraction PI I afforded after ion exchange chromatography on SE-Sephadex two isoinhibitors, PI IA (Mr approximately 18 000; pI approximately 6.3) and PI IB (Mr approximately 19 500; pI approximately 7.2). The chromatography of fraction PI II on SE-Sephadex yielded three inhibitors of approximately equal molecular weight (Mr approximately 13 500), PI IIC (pI approximately 6.3), PI IID (pI approximately 7.7), and PI IIE (pI approximately 9.1). All the inhibitors isolated show a high activity toward trypsin, acrosin, and chymotrypsin. Unlike the two isoinhibitors of PI I, which practically do not inhibit kallikrein, inhibitors PI II show an effect on this enzyme. Neither the isoinhibitors of PI I nor inhibitors PI II are active toward cathepsin D.
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PMID:Polyvalent proteinase inhibitors from potatoes. Isolation and characterization of acrosin inhibitors from Solanum tuberosum. 704 Jan 19

Reduced turn-over of tau by calpains is a possible mechanism to facilitate the incorporation into paired helical filaments (PHFs) in Alzheimer's disease. The present study shows that the differently phosphorylated fetal tau isoforms are all rapidly proteolysed to an equal extent by human brain m-calpain. This result argues against the hypothesis that this type of fetal phosphorylation is involved in reducing tau turn-over by calpain in Alzheimer's disease. Adult and fetal tau fragments in vitro generated by m-calpain, but not trypsin, cathepsin D or chymotrypsin resemble the post-mortem in situ degradation patterns, suggesting a possible role for calpains in tau metabolism in vivo. Tau incorporated into PHFs was considerably more resistant to proteolysis by calpain which can help to explain the persistence of these structures in Alzheimer's disease.
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PMID:Differential sensitivity to proteolysis by brain calpain of adult human tau, fetal human tau and PHF-tau. 761 58

DMP 323 is a potent inhibitor of the protease of human immunodeficiency virus (HIV), with antiviral activity against both HIV type 1 and HIV type 2. This compound is representative of a class of small, novel, nonpeptide cyclic urea inhibitors of HIV protease that were designed on the basis of three-dimensional structural information and three-dimensional database searching. We report here studies of the kinetics of DMP 323 inhibition of the cleavage of peptide and HIV-1 gag polyprotein substrates. DMP 323 acts as a rapidly binding, competitive inhibitor of HIV protease. DMP 323 is as potent against both peptide and viral polyprotein substrates as A-80987, Q8024, and Ro-31-8959, which are among the most potent inhibitors of HIV protease described in the literature to date. Incubation with human plasma or serum did not decrease the effective potency of DMP 323 for HIV protease, suggesting that plasma protein binding is of a low affinity relative to that of HIV protease. DMP 323 was also assessed for its ability to inhibit the mammalian proteases renin, pepsin, cathepsin D, cathepsin G, and chymotrypsin. No inhibition of greater than 12% was observed for any of these enzymes at concentrations of DMP 323 that were 350 to 40,000 times higher than that required to inhibit the viral protease 50%.
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PMID:Potency and selectivity of inhibition of human immunodeficiency virus protease by a small nonpeptide cyclic urea, DMP 323. 797 96

Potato tubers contain a complex group of proteins of 20 to 24 kDa that exhibit homology to Kunitz-type proteinase inhibitors. We isolated three cDNAs and two genomic clones that encode members of the potato Kunitz-type proteinase inhibitor (PKPI) family. Comparison of the structures of these and other cloned genes indicated that genes of the PKPI family can be classified into three major homology groups, namely, A, B and C. The PKPI-A and -B genes exhibit higher homology to one another than to the PKPI-C genes. Determination of the N-terminal amino acid sequences of 18 polypeptides from the complex group of 20- to 24-kDa proteins that had been separated by column chromatography and subsequently gel electrophoresis revealed three different sequences that corresponded to PKPI-A, -B, and -C. PKPI-A genes include those coding for a cathepsin D inhibitor, while PKPI-B and -C genes include those coding for trypsin and/or chymotrypsin inhibitors and a subtilisin inhibitor. Precursors to PKPIs are synthesized with an N-terminal extra peptide that appears to contain, in addition to the signal peptide, a short propeptide with a highly conserved Asn-Pro-Ile-Xxx-Leu-Pro motif that is identical to the potential vacuolar-sorting determinant in the N-terminal propeptide of a precursor to sporamin of sweet potato. Expression of the PKPI-A and -B genes is differentially regulated: PKPI-A mRNA but not PKPI-B mRNA were induced in leaves after wounding or upon treatment with methyl jasmonate. Nuclear genes for PKPI-A and -B do not contain introns, and the homology between the two types of gene extends only 72 bp upstream from the site of initiation of transcription.
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PMID:A family of potato genes that encode Kunitz-type proteinase inhibitors: structural comparisons and differential expression. 806 93

The alternatively spliced type III connecting segment (IIICS) of fibronectin (Fn) contains an amino acid sequence, CS-1, which is recognized by the integrin receptor, alpha 4 beta 1. Plasma Fn inhibits alpha 4 beta 1-dependent binding of lymphocytes and monocytes to CS-1 containing Fn derivatives poorly, suggesting limited exposure of the CS-1 sequence in Fn. To test the availability of CS-1 in plasma Fn, an antibody was raised to the synthetic peptide CS-1. The CS-1 sequence was found to be minimally exposed in plasma Fn; and immobilization of Fn, a model of matrix deposition, caused only a modest increase in its exposure. Digestion of Fn with selected proteases, however, induced substantial expression of the CS-1 sequence. The acid protease cathepsin D generated fragments of 31-33.5 kDa from the COOH-terminal heparin-binding domain of Fn which possessed high immunoreactivity with anti-CS-1. Digestion of Fn with cathepsin B also resulted in the exposure of CS-1 sequence in a 140 kDa fragment. Although the digestion of Fn with neutral proteases (neutrophil elastase, cathepsin G, chymotrypsin, trypsin) generated fragments from the COOH-terminal heparin-binding domain of similar molecular weight as with cathepsin D, the exposure of CS-1 did not occur. Exposure of the CS-1 region by the cathepsins was supported by cell adhesion experiments; digestion of Fn with cathepsins D and B transformed inert plasma Fn to an effective inhibitor of adhesion of lymphoblastoid B and T cells (Ramos, Jurkat, Molt-4) to an immobilized CS-1 conjugate. These results suggest that exposure of the CS-1 sequence in plasma Fn by proteolysis with cathepsins D and B, enzymes implicated in several pathological processes, may serve a regulatory function in cell adhesion. The adhesive function of the CS-1 region in intact Fn appears to be suppressed by the native conformation of the molecule.
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PMID:Proteolysis regulates exposure of the IIICS-1 adhesive sequence in plasma fibronectin. 871 84

N-Pepstatinyl-N'-dansyldiaminopropane (dansyl-pepstatin) was prepared by the coupling of pepstatin A and N-dansyl-diaminopropane. The dansyl-pepstatin obtained strongly inhibited pepsin activity by forming a 1:1 complex. The fluorescence of the dansyl group (excitation at 320 nm, and emission near 520 nm) increased with the formation of the complex. The increase in fluorescence of dansyl-pepstatin solution was proportional to the amount of added pepsin, chymosin and cathepsin D until dansyl-pepstatin was saturated by these enzymes and at higher protease concentrations the fluorescence did not increase further. Therefore, the net amounts of active pepstatin-sensitive carboxyl proteases could be determined by detecting the inflection point of increased fluorescence upon addition of the protease to a dansyl-pepstatin solution of known concentration. Moreover, the protease concentrations of many samples were obtained easily by measurements of increased fluorescence compared with that caused by authentic protease solution. The minimum detectable amount of pepsin was about 20 pmol. On the other hand, the fluorescence did not increase upon mixing with inactivated pepsin, chymotrypsin, or trypsin. The K(i) value of dansyl-pepstatin for pepsin was similar to that of pepstatin A. It was possible to determine the amount of chymosin contained in rennet by this method. The inactivation curve of pepsin in pH 6.5 buffer was also determined quickly and easily by the use of this method. This assay method for pepstatin-sensitive carboxyl proteases is very simple and easy, and it is possible to determine the net amounts of active pepstatin-sensitive carboxyl proteases even in crude mixtures.
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PMID:Determination of pepstatin-sensitive carboxyl proteases by using pepstatinyldansyldiaminopropane (dansyl-pepstatin) as an active site titrant. 937 5

Three protein inhibitors of proteolytic enzymes with molecular weights 21, 22, and 23 kD were isolated from potato tubers (Solanum tuberosum L.) by ammonium sulfate precipitation followed by gel and ion-exchange chromatography. The 21- and 22-kD proteins were shown to be serine proteinase inhibitors with different specificities. The 21-kD protein inhibits human leucocyte elastase and trypsin effectively, but it is less effective towards chymotrypsin. The 22-kD protein is an inhibitor of cysteine proteinases and suppresses the activities of papain, ficin, and bromelain with the same affinities. None of the isolated proteins inhibit subtilisin, pepsin, or cathepsin D. The 21-kD protein consists of two disulfide-linked polypeptide chains with molecular weights of 16.5 +/- 1 kD and 4.5 +/- 1 kD. The 22-kD and 23-kD proteins have a single polypeptide chain. The N-terminal 22-25 amino acid sequences of these three proteins were determined. These sequences have significant homology to other plant inhibitors from the Kunitz soybean inhibitor superfamily.
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PMID:Potato tuber protein proteinase inhibitors belonging to the Kunitz soybean inhibitor family. 948 70

The levels of marker enzymes for liver function, namely transaminases (SGPT, SGOT), creatine phosphokinase (CPK), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were estimated in the sera of burn patients by administering trypsin: chymotrypsin preparation and comparing with an untreated group. Neutrophil proteolytic activity was also measured by assaying the lysosomal enzymes, namely neutrophil elastase and cathepsin D. Our earlier studies have already proved the efficacy of the above enzyme preparation to burn patients on the enhancement of vascular responses during the acute phase of the burn injury. These beneficial responses were brought about by the modulation of acute phase proteins expressed in the liver. Hence, it is of interest to study the changes in the above mentioned liver enzymes and certain lysosomal enzymes in the serum during the first 10 days of burn injury. The levels of liver and lysosomal enzymes markedly decreased in the treated group when compared with the untreated group. The enzyme studies clearly indicated that the initial rise in the liver enzymes was minimized in the treated group when compared with the untreated group and this helped in reducing the stress to the liver in the treated cases. The increase in the activity of alpha 1-antitrypsin and alpha 2-macroglobulin and decreased levels of C-reactive protein are attributed to the reduction of proteolytic enzyme levels in the treated group and minimizing the degradative changes during wound repair.
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PMID:Serum enzymatic changes modulated using trypsin: chymotrypsin preparation during burn wounds in humans. 956 24


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