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 domain structure of human fibronectins isolated from plasma and from the conditioned medium of normal and transformed fibroblasts was analyzed by limited proteolysis and S-cyanylation followed by immunostaining of released fragments with five kinds of antibodies, each specific for one functional domain. The results indicate that all three human fibronectins are composed of the same set of functional domains aligned in the same topological order. However, the following clear differences were found in specific fragments released from plasma fibronectin (pFN) and those released from fibronectin of normal (N-cFN) and transformed fibroblasts (T-cFN). Two fragments (Mr = 70,000 and 60,000) were released from the COOH-terminal region of pFN by cathepsin D. These fragments represent the COOH-terminal heparin-binding (Hep-2) and fibrin-binding (Fib-2) domains. The corresponding fragments released from both N-cFN and T-cFN by cathepsin D had much larger molecular weights (Mr = 100,000 and 83,000-74,000) than those from pFN. The fragments from the Fib-2 domain alone, however, did not show any difference among all three FNs. The internal region, from the gelatin-binding (Gel) domain through the Hep-2 domain, of N-cFN and T-cFN was released as a Mr = 210,000 fragment upon mild trypsin digestion. The corresponding fragment from pFN was released as a Mr = 185,000 fragment. The COOH-terminal half, including the Hep-2 domain, of both N-cFN and T-cFN was released by S-cyanylation as Mr = 160,000-145,000 fragments, which are 25,000-20,000 larger than the corresponding fragments of pFN. These results clearly indicate that the Hep-2 domain of N-cFN and T-cFN is 30,000-20,000 daltons larger than the same domain of pFN. Although various fragments released from N-cFN and T-cFN showed a similar pattern, there were minor differences. Thermolysin fragments derived from the Hep-2 domain of N-cFN were clearly distinguishable from those from T-cFN. Three groups of fragments with Mr = 40,000, 35,000-32,000, and 30,000 were released from N-cFN, while only the 35,000-32,000 fragment was released from T-cFN. The Mr = 44,000/60,000 thermolysin fragments representing the Gel domain and the Mr = 210,000/165,000 tryptic fragments representing the internal domains of T-cFN were slightly, but consistently, larger than those of N-cFN.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Differences in domain structure between human fibronectins isolated from plasma and from culture supernatants of normal and transformed fibroblasts. Studies with domain-specific antibodies. 398 46

1. An enzyme system present in a rat liver lysosome-rich fraction was found to liberate soluble hydroxyproline-containing products from insoluble collagen, with maximum activity at pH3.45. It was concluded that a form of cathepsin D was involved since synthetic substrates specific for trypsin were not hydrolysed. Collagenolysis was enhanced by thiol compounds and inhibited by Cu(2+) ions and the anti-inflammatory drugs phenylbutazone and ibufenac. 2. The possibility that behaviour of collagen and collagenolysis were modified by various substances, either by destruction of intramolecular and intermolecular bonds in tropocollagen or by electrostatic interactions, is discussed. Insoluble collagen was found to bind electrostatically to chondromucoprotein. This interaction was inhibited by some anti-inflammatory drugs. 3. Possible roles of the lysosomal collagenolytic enzyme system in experimental lathyrism in rats given penicillamine, and in erosion of cartilage in rheumatoid arthritis, are considered. 4. Collagenolysis in vivo, which may depend on complex interrelationships between collagen, chondromucoprotein and metal ions, is discussed in relation to possible effects, both harmful and beneficial, of anti-inflammatory drugs used in rheumatoid arthritis.
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PMID:Effects of lysosomal collagenolytic enzymes, anti-inflammatory drugs and other substances on some properties of insoluble collagen. 580 7

1. Acid proteinase from rabbit liver lysosomes was purified about 1000-fold, on a protein basis. 2. The purification procedure involved isolation of a lysosomal-mitochondrial pellet and conversion of this into an acetone-dried powder. 3. The enzyme was extracted with an acidic buffer and subjected to column chromatography with DEAE-Sephadex and Sephadex G-100. 4. The molecular weight of the enzyme was 50000-52000. 5. Maximal activity against haemoglobin was obtained at pH3.2; serum albumin was attacked, but very much more slowly. 6. Several possible inhibitors of the enzyme were tested. Thiol-blocking reagents, several inhibitors of trypsin and chymotrypsin, and a chelating agent were without effect. 7. The enzyme was competitively inhibited by 3-phenylpyruvic acid at low concentrations. 8. Dithiothreitol caused rapid inactivation of the enzyme at pH8. 9. It is concluded that this enzyme is a form of cathepsin D, which may be widely distributed in lysosomes.
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PMID:Lysosomal acid proteinase of rabbit liver. 605 10

A protein solubilized in Tris-HCl/saline buffer from keratinized cells of newborn rat epidermis exhibited inhibitor activity to papain and ficin, but not to trypsin, cathepsin D and pepsin. This protein was purified from keratinized cells as well as nonkeratinized and germinative cells by means of IgG affinity chromatography. The inhibitors extracted from all cell layers were immunologically identical and had a molecular weight of approximately 12,500 +/- 500. Since amino acid analysis showed that the inhibitor contains about 35 residues of glycine per mol, [3H]glycine was used to investigate synthesis of the protein. The inhibitor from nonkeratinized and germinative cells was radioactively labeled by 2 h after injection and appeared in keratinized cells by 48 h after injection. Indirect immunofluorescence microscopy demonstrated in situ distribution of the protein in the entire epidermis, and the protein localized by the plasma membrane in granular cells and diffusely in keratinized cells was shown to be insoluble in Tris-HCl saline buffer. The results indicate that a thiol-proteinase inhibitor is synthesized in epidermal cells during keratinization and is retained as part of the cytoplasmic structure
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PMID:Chemical characterization, synthesis and distribution of proteinase inhibitor in newborn rat epidermis. 615 44

Extracts of rheumatoid synovial tissue obtained at surgical synovectomy contained neutral proteinases as well as cathepsin D. The neutral proteinase activity was particle-bound but could be solubilized by 1 M MgCl2. About half of the solubilized activity adsorbed to aproptinin-Sepharose at pH 7.5 and was desorbed at pH 3.3. This activity was shown to be due to leukocyte elastase and cathepsin G by enzymological and immunological criteria. The neutral proteinase activity that did not adsorb to aprotinin-Sepharose was not due to elastase or cathepsin G. It was able to hydrolyse proteoglycan and was inhibited by diisopropylfluorophosphate, soybean and lima bean trypsin inhibitors. It was, therefore, a serine proteinase. Its inhibition characteristics were different from those of plasmin, kallikrein or thrombin. All of the neutral proteinase activity of synovial extracts was attributable to serine proteinases, no evidence of metallo-proteinases was found. The possible role of the neutral proteinases in the degradation of the matrix of cartilage is discussed. A simple procedure for purifying leukocyte elastase and cathepsin G is described as well as the raising of specific antisera to these enzymes.
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PMID:Identification of proteinases in rheumatoid synovium. Detection of leukocyte elastase cathepsin G and another serine proteinase. 615 6

Monoclonal antibodies to human plasma fibronectin were used to study the topological arrangement of several biologically active sites on the 220,000-dalton fibronectin subunit. Plasma fibronectin was cleaved into a number of biologically active fragments by trypsin and cathepsin D. Fragments that bind gelatin and heparin bind to both gelatin and heparin were isolated by affinity chromatography. These fragments were further characterized by their ability to bind to two different monoclonal antibodies: monoclonal 2-8 and monoclonal 180-8. Using this approach, we have established the positions of two unique heparin-, a gelatin-, and two monoclonal antibody-binding sites on the fibronectin subunit.
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PMID:Localization of two unique heparin binding domains of human plasma fibronectin with monoclonal antibodies. 617 83

Treatment of mouse peritoneal macrophages by gamma (type II, immune) interferon depressed the ingestion of non-opsonized Escherichia coli mediated by the non specific receptor, and also the intracellular degradation of the ingested bacteria. These effects were time and dose-dependent, and sensitive for trypsin and pH 2 treatment. The intracellular concentration of three lysozomal enzymes, beta-glucuronidase, acid phosphatase and cathepsin D, was elevated in gamma interferon-treated macrophages.
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PMID:Effect of gamma interferon preparations on in vitro phagocytosis and degradation of Escherichia coli by mouse peritoneal macrophages. 618 84

The papain inhibitor from human spleen was purified by extraction in isotonic sucrose, acetone fractionation, papain-Sepharose affinity chromatography and gel filtration on Sephadex G-50. The purified inhibitor was fractionated by electrofocusing into four major isoelectric variants with pI values of 4.7, 5.0, 6.0 and 6.5. These variants can be classified into two groups: the acidic type, comprising the variants with pI 4.7 and 5.0, and the neutral type, comprising the variants with pI 6.0 and 6.5. The following properties distinguish the two types: 1. Immunological properties: antibodies raised against either of the neutral variants precipitated both of these, but not the acidic variants. The antiserum against the human epidermal cysteineproteinase inhibitor precipitated the acidic variants, but not the neutral variants. 2. Molecular size: two-dimensional electrophoresis of the purified inhibitor gave molecular weights of 11400 for the acidic variants and 12000 for the neutral variants. The pI 6.0 variant contained two compounds with molecular weights of 12000 and 12800. 3. Enzyme spectrum: human cathepsin B was inhibited by the acidic type, while the neutral type was a poor inhibitor. Both types inhibited cathepsin H, papain, ficin and bromelain, although the inhibition of bromelain did not exceed 70%. Human cathepsin D, bovine trypsin and chymotrypsin and porcine elastase were not inhibited by either type.
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PMID:Human spleen cysteineproteinase inhibitor. Purification, fractionation into isoelectric variants and some properties of the variants. 618 75

Plasma fibronectin is one of the largest plasma proteins (Mr approximately 440 000), comprising two approximately equal polypeptide chains which are held together by a disulfide linkage near the C-terminal end of the molecule. The binding of gelatinized latex beads to liver slices as well as the internalization of these particles by macrophages, in the presence of heparin, is greatly enhanced by fibronectin. The question as to whether the entire covalent structure of fibronectin was necessary for opsonizing activity was approached by limited proteolytic degradations of the molecule. Patterns of controlled digestion with trypsin, cathepsin D, Staphylococcus aureus protease, and plasmin all indicate that the minimal unit necessary for retention of opsonic activity is some large (Mr 200 000 and 190 000) single-chain entity. Treatment with plasmin proved to be the most reliable procedure for generating the active split product which could be readily separated from the inactive, disulfide-containing C-terminal fragment. Incorporation of dansylcadaverine into plasma fibronectin (3.5 mol/mol of protein) by fibronoligase (coagulation factor XIIIa) did not affect the opsonic activity of the protein.
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PMID:Enzymatic modifications of human plasma fibronectin in relation to opsonizing activity. 622 71

We have demonstrated that incubation of rat liver microsomes with N-hydroxy-2-acetylaminofluorene (N-OH-AAF) leads to formation of a 2-nitrosofluorene-membrane lipid adduct. This adduct exists as a nitroxyl free radical, termed N-O-LAF, in its oxidized state. When microsomes were incubated with the sulfhydryl binding agent, rho-hydroxymercuribenzoate, a larger amount of N-OL-LAF formed. We interpret this as a slowdown in the rate of endogenous chemical reduction of carcinogen-membrane lipid adduct. In this paper we present evidence that N-OH-AAF is deacetylated by a microsomal enzyme to form N-hydroxy-2-aminofluorene and this is then oxidized to 2-nitrosofluorene which adds covalently to membrane lipid double bonds to form N-O-LAF. Various antioxidants, peroxidase inhibitors, and P450 substrates and inhibitors were ineffective in altering the amount of N-O-LAF formed from N-OH-AAF; but two esterase inhibitors, dietyl-rho-nitrophenylphosphate and alpha-toluene-sulfonyl fluoride, prevented N-O-LAF formation. Of the following purified enzymes tested: porcine liver carboxyl esterase, pepsin, chymotrypsin, cathepsin D, ficin, papain, leucine aminopeptidase, Naja naja phospholipase, acetylcholinesterase (type I), trypsin (type I and V) and epoxide hydrase; only carboxyl esterase was effective in deacetylating N-OH-AAF.
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PMID:The deacetylation of N-hydroxy-2-acetylaminofluorene by rat liver microsomes and carboxyl esterase. 626 Mar 32


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