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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amyloid protein precursor (APP) of Alzheimer's disease was found to bind saturably (Kd = 60 nM) to embryonic chick brain extracellular matrix (ECM). The binding of APP to ECM was not inhibited by 10 micrograms/ml heparin or heparan sulfate. However, pretreatment of cells with 1 mM 4-methylumbelliferyl-beta-D-xyloside, an inhibitor of proteoglycan biosynthesis, reduced the number of APP binding sites on the ECM by 80%. The binding of APP to ECM was also inhibited by pretreatment with chlorate, an inhibitor of glycan sulfation, and heparitinase, which digests the carbohydrate component of heparan sulfate proteoglycans. These results suggest that APP binds with high affinity to one or more heparan sulfate proteoglycans. Acidic and basic fibroblasts growth factor (FGF) also bound to chick ECM. When ECM was incubated with a protease associated with the enzyme AChE (AChE-AP), APP and acidic FGF were released intact from the matrix. The AChE-AP was at least 100-fold more potent in releasing APP from ECM than other trypsin-like proteases (trypsin, plasmin, thrombin). The action of the AChE-AP was inhibited by glia-derived nexin (protease nexin I) and by human brain APP at low nanomolar concentrations. These results suggest that in vivo an AChE-AP may cleave ECM proteins to regulate the availability of soluble APP or other factors bound to the ECM.
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PMID:Association and release of the amyloid protein precursor of Alzheimer's disease from chick brain extracellular matrix. 127 36

Squid cranial cartilage has been found to contain three different proteoglycan populations, two of which form aggregates (Vynios, D.H. and Tsiganos, C. P., Biochim. Biophys. Acta 1033: 139-147, 1990). The aggregation involves interaction of their protein cores as assessed by electron microscopy and biochemical data. Aggregating oligopeptides were isolated after mild trypsin digestion which inhibited self-aggregation of proteoglycans. The aggregation does not involve interaction of the side chains of polar amino acids and evidence is provided that it is mediated through hydrophobic interaction. It is enhanced upon concentration or incubation of the samples at 37 degrees C.
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PMID:Self-aggregation of squid cranial cartilage proteoglycans. 128 10

We investigated the effect of ulinastatin, a candidate anti-osteoarthritic drug, in comparison with indomethacin and triamcinolone, two well-known drugs for osteoarthritis, on IL-1 production by monocytes, proteoglycan synthesis by chondrocytes and superoxide generation by leukocytes. Ulinastatin, a glycoprotein purified from human urine, suppressed both the IL-1 production and the IL-1 induced reduction of proteoglycan synthesis. In addition, ulinastatin inhibited superoxide generation. These actions of ulinastatin seemed to be related to its inhibitory actions against serine proteases such as trypsin, alpha-chymotrypsin, plasmin, leukocyte elastase and leukocyte cathepsin G. Triamcinolone suppressed the IL-1 production more potently than ulinastatin and it also suppressed the IL-1 induced reduction of proteoglycan synthesis. Triamcinolone alone, however, reduced the proteoglycan synthesis, and it did not affect the superoxide generation. In contrast, indomethacin had no effect on proteoglycan synthesis and superoxide generation, although it accelerated the IL-1 production. These results indicate that these three drugs have different mechanisms of action on the factors involved in the pathogenesis of osteoarthritis. Since ulinastatin has broad actions, which are considered to be beneficial for preventing some process of osteoarthritic pathogenesis, ulinastatin is expected to be an useful drug for the treatment of osteoarthritis.
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PMID:[Mechanism of the anti-osteoarthritic action of ulinastatin in comparison with those of indomethacin and triamcinolone]. 131 79

In vitro, cartilage proteoglycans (PGs) are effective inhibitors of hydroxyapatite formation and growth. Their inhibitory ability decreases with decreasing PG size and charge density. It has been suggested that the enzyme-mediated alteration in the size and conformation of PGs in the growth plate may similarly facilitate the calcification process. In this study, a gelatin gel system was used to monitor hydroxyapatite formation and growth in the presence of proteoglycan aggregates, before and after enzyme treatment. To reproduce the physeal degradation cascade, an enzyme preparation was used that contained all of the growth plate enzymes. At a concentration of 500 micrograms/ml, the untreated proteoglycan aggregates reduced the amount of mineral formed by 30%. When the aggregates were treated with the heat-inactivated enzyme, the same extent of inhibition was found. In contrast, treating the aggregates with the crude growth plate enzyme preparation removed all the inhibitory ability, such that 500 micrograms/ml of proteoglycan preparation yielded 10% more mineral than the controls. Treatment of the aggregates with chondroitinase ABC and trypsin, similarly removed all the inhibitory ability. These data, suggest that enzymatic degradation of proteoglycans may contribute to the regulation of growth plate calcification.
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PMID:Treatment of proteoglycan aggregates with physeal enzymes reduces their ability to inhibit hydroxyapatite proliferation in a gelatin gel. 131 95

A new ligand for syndecan (a cell surface heparan sulfate-rich proteoglycan) has been discovered. In the solid-phase binding assay utilizing small nitrocellulose discs to immobilize matrix molecules, binding of syndecan to neurite growth-promoting protein, p30/amphoterin, was observed. This binding was strongly dependent on the concentration of amphoterin used to coat the discs, but was saturable with an excess amount of syndecan. The interaction was inhibitable with heparan sulfate and heparin but less effectively with chondroitin sulfate, indicating that heparan sulfate chains of syndecan were involved in the binding. Anti-amphoterin antibodies inhibited the binding partially. Mouse mammary epithelial cells were shown to bind amphoterin directly but not after trypsin treatment or in the presence of heparin and to produce amphoterin in the extracellular space. Both syndecan and amphoterin were found to localize on lateral surfaces of newly adhered mammary epithelial cells. Toward confluency amphoterin amounts decreased. Because amphoterin can be localized to the same sites with syndecan and because of their interaction, amphoterin is a new putative pericellular ligand for syndecan. These interactions may be involved in the regulation of cell behavior.
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PMID:Neurite growth-promoting protein (amphoterin, p30) binds syndecan. 136 84

Synthesis of sulphated proteoglycans was compared in human erythroleukaemia (HEL) cells grown under control conditions and under stimulation by dimethyl sulphoxide (DMSO) and phorbol 12-myristate 13-acetate (PMA). Synthesis of [35S]sulphate-labelled proteoglycans by DMSO-treated cells was decreased by about 35% relative to controls, but synthesis of proteoglycans by PMA-treated cells increased 3-4-fold. Control and DMSO-treated cells secreted 65% of the newly synthesized proteoglycans, but PMA-treated cells secreted more than 90%. Sepharose CL-6B chromatography and SDS/PAGE suggested the presence of several proteoglycans in the cells and culture medium. The PMA-treated cells synthesized a low-Mr proteoglycan (Kav. 0.3( that was not present in controls and DMSO-treated cultures. The proteoglycans of the cells and medium from control, DMSO-treated and PMA-treated cultures could be separated into three fractions by octyl-Sepharose chromatography. The proteoglycans were resistant to trypsin but were degraded by Pronase and papain to fragments similar in size to the NaOH/NaBH4-generated glycosaminoglycans. The average chain length of the glycosaminoglycans (Kav. 0.20 on Sepharose CL-6B for controls) was decreased by DMSO (Kav. 0.25) and by PMA (Kav. 0.30-0.38). Chondroitin ABC lyase digestion of the proteoglycans from the medium of the control cultures produced two core proteins at Mr 31,000 and 36,000. The DMSO medium proteoglycans had only the 31,000-Mr core protein, and the PMA culture medium proteoglycans had core proteins of Mr 27,000, 31,000 and 36,000. Changes in synthesis of proteoglycans induced by DMSO or PMA may have relevance for the maturation of haematopoietic cells.
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PMID:Proteoglycan synthesis in human erythroleukaemia (HEL) cells. 137 1

Monoclonal antibodies were raised that specifically recognize the NH2-terminal neoepitope sequence present in link protein cleavage products derived from stromelysin-degraded proteoglycan aggregate. Competitive enzyme-linked immunosorbent assay, using synthetic peptides as inhibitors, showed that one of these antibodies (CH-3) required, for antibody recognition, the free NH2-terminal amino acid isoleucine (residue 17 of the intact protein) in the sequence NH2-IQAENG at the stromelysin cleavage site of link protein 3. Human proteoglycan aggregate was digested with recombinant human stromelysin, bovine chymotrypsin, bovine trypsin, and porcine elastase, and their respective link protein degradation products were tested for immunoreactivity with antibody CH-3. Only stromelysin- and chymotrypsin-generated link protein 3 were recognized by antibody CH-3. Both of these enzymes generate link protein NH2 termini with the sequence 17IQAENG. . .; hence these studies indicated that monoclonal antibody CH-3 recognized this neoepitope sequence in only specific proteolytically modified link protein molecules. Since the occurrence of link protein 3 increases with aging, the incidence of CH-3 epitope in proteoglycans isolated from human knee articular cartilage of individuals of different ages was investigated. The prevalence of CH-3 epitope was found to be highest in newborn and adolescent articular cartilage samples. However, little CH-3 epitope was detected in older adult cartilage, although considerably more link protein 3 was present in these samples. These results suggest that additional proteolytic agents are responsible for the increased occurrence of link protein degradation products with aging.
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PMID:Monoclonal antibodies recognizing protease-generated neoepitopes from cartilage proteoglycan degradation. Application to studies of human link protein cleavage by stromelysin. 137 86

We have identified a unique mesangial matrix protein of the human glomerulus by using a monoclonal antibody, 1G10, generated against culture human glomerular cells. By immunofluorescence, the antigen recognized by 1G10 (1G10 antigen) is present in mesangium and smooth muscle tissue and cannot be detected in any other tissue examined. Immunoelectron microscopy of glomeruli indicated that 1G10 antigen is present exclusively in the mesangial matrix at the endothelial-mesangial interface. The 1G10 antigen is also expressed by cultured mesangial cells, but not by cultured glomerular epithelial cells, umbilical endothelial cells or fibroblasts. 1G10 did not react with the mesangial matrix proteins [fibronectin (FN), laminin (LAM), collagen types I, III, IV, V, and VI (Col I, III, IV, V, VI), heparin sulfate proteoglycan (HSPG), or thrombospondin (TS)] present under normal and diseased states or smooth muscle antigens (myosin, actin), but did react with a 4 M urea extract of renal cortex and a 0.3% deoxycholate extract of isolated glomeruli. Two dimensional immunoblot analysis using the urea extract demonstrated the binding of 1G10 to an approximately 200 KDa polypeptide with pI 6.0. On one dimensional immunoblot this band did not show cross react with polyclonal antisera to FN, LAM, Col IV, V, VI, HSPG or TS. This mesangial matrix component is trypsin and periodate sensitive, suggesting that it has the character of glycoprotein. In renal biopsy specimens from patients with mesangial proliferative glomerulonephritis (GN) and membranoproliferative GN, the expression of the 1G10 antigen increased along with mesangial hypercellularity or increased accumulation of mesangial matrix, but decreased in completely sclerosed glomeruli. No significant changes in 1G10 antigen expression was observed in membranous GN or minimal change nephrosis compared to normal glomeruli. This study suggests that the 1G10 antigen may not only be a useful marker for the clinical assessment of GN, but may also serve as a potential tool for the study of the pathogenesis of glomerular diseases characterized by cellular proliferation and mesangial matrix expansion.
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PMID:A monoclonal antibody (1G10) recognizes a novel human mesangial antigen. 140 47

Heparan sulphate proteoglycans are rapidly released from VACO 10MS colon cancer cells that are triggered with phorbol esters to undergo terminal differentiation. This lag-free temperature-sensitive process is correlated with a conversion of the lipophilic proteoglycans of the cell surface into non-lipophilic proteoglycans that accumulate in the culture medium. The released proteoglycans are very similar to their lipophilic precursors in size, buoyant density and glycosaminoglycan characteristics; however, they exhibit slightly smaller core proteins after chemical and enzymic deglycosylation. The lipophilicity of the larger-sized core proteins of the cell-associated proteoglycans is also correlated with the presence of an easily iodinatable domain; this domain is missing in the released proteoglycans. Exogenous proteases (i.e. chymotrypsin, V8, trypsin and proteinase K) readily cleave this segment from the larger protease-resistant region of the proteoglycan structure. It is also released intact by treatment of the isolated proteoglycans with methanolic HCl. This component appears to be peptide in character, in that proteases readily degrade it and release iodotyrosines when the precursor has been iodinated. No evidence for the presence of covalently attached fatty acids in the cell-associated proteoglycans was found. These results are consistent with the hypothesis that the altered proteoglycan metabolism that is associated with the phorbol-ester-induced terminal differentiation of certain human colon cancer cells ensues upon the activation of a membrane-localized protease that cleaves a lipophilic anchor segment from the cell surface proteoglycans.
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PMID:Release of cell surface proteoglycans from differentiating colon cells proceeds by cleavage of lipophilic anchor peptides. 141 65

To demonstrate the intra- and extracellular localization of hyaluronic acid (HA) in articular cartilage of the rabbit tibia, biotinylated HA binding region, which specifically binds to the HA molecule, was applied to the tissue. In comparison with the localization of HA, that of chondroitin sulfate (CS), keratan sulfate (KS), and the protein core (PC) of the proteoglycan was examined by immunohistochemistry. Strong positive staining for HA was detected in chondrocytes located in the transition between the superficial and middle zones of the tissue. Pre-treatment with chondroitinase ABC, keratanase II, or trypsin enhanced the stainability for HA in peri- and intercellular matrices. Immunohistochemistry with or without enzymatic pre-treatment demonstrated that immunoreactivity for CS, KS, and PC was distinctly discerned in chondrocytes and in the extracellular matrix located in the middle and deep zones. In particular, the immunoreactivity for KS and PC was augmented by pre-treatment with chondroitinase ABC not only in chondrocytes but in the extracellular matrix located in the middle and deep zones. Microbiochemical analysis corresponded well with histochemical and immunohistochemical results. These results suggest that HA is abundantly synthesized and secreted in chondrocytes located in the transition between the superficial and middle zones.
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PMID:Intra- and extracellular localization of hyaluronic acid and proteoglycan constituents (chondroitin sulfate, keratan sulfate, and protein core) in articular cartilage of rabbit tibia. 143 Oct 58


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