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)

Fibronectins are multimeric, adhesive glycoproteins present on cell surfaces and circulating in blood. Cellular fibronectin produced by fibroblasts in vitro and fibronectin isolated from plasma are known to be very similar immunologically and biochemically. We investigated whether or not they are identifical. Purified chicken and human cell-surface fibronectins are 150-fold more active in hemagglutination of fixed erythrocytes than plasma fibronectins. Cell-surface fibronectin is also 50-fold more active in restoring a more normal morphology to transformed cells originally missing the protein. However, in two other assays that measure cell attachment to collagen and cell spreading, cell-surface and plasma fibronectins have identical specific activities. In sodium dodecyl sulfate polyacrylamide gels, the subunits of human and chicken plasma fibronectins have significantly smaller apparent subunit molecular weights than cellular fibronectins present on cell surfaces or secreted into culture media. These differences are also present in a characteristic large subfragment of both forms of fibronectin after limited proteolysis by trypsin. We conclude that by both biological and biochemical criteria, cellular and plasma fibronectins are similar but not identical.
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PMID:Fibroblast cellular and plasma fibronectins are similar but not identical. 45 56

The state of chick embryo chondroblasts in culture was found to be sensitive to both fibronectin and another substance(s) (activity A) which could be extracted from chick embryo fibroblasts with 1 M urea or from conditioned medium. In the presence of either of these activities at concentrations of 25-150 micrograms/ml, chondroblasts, which normally grow as mixed cultures of floating and adherent cells, all immediately became attached to the tissue culture dish and spread. After several days, the morphology of these typically epithelioid cells became fibroblastic. This did not involve a selection process, since the effect was reversible. The synthetic program of these cells was also dramatically modified: the cultures no longer synthesized the chondroblast-unique type IV sulfated proteoglycan and began synthesizing alpha 2 collagen chains typical of fibroblastic or early limb bud cells. Fibronectin was resolved from activity A by gelatin affinity chromatography or gel filtration. Both activities were trypsin-sensitive. The two activities differed, however, on the basis of how the protein fractions in which they were found migrated in SDS-polyacrylamide gels, their specific activities and their effects on cell morphology and cell growth.
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PMID:Fibronectin alters the phenotypic properties of cultured chick embryo chondroblasts. 47 27

Methods are described for culture of intact or trypsin-digested adult guinea pig glomeruli. Cell types grown from intact glomeruli were distinctly different from those which dominated cultures of trypsin dissociated glomerular cells as determined by transmission and scanning electron microscopy as well as by fluorescence or enzyme cytochemical reaction with lectins and immunofluorescence cytochemical staining for actin or fibronectin. Cells with long cytoplasmic extensions (glomerular epithelial cells), cultured from intact glomeruli, have strong affinity for concanavalin-A and soybean agglutinin which react with glucose and galactose residues respectively. Rectangular cells (glomerular mesangial cells), cultured as the predominant cell from trypsinized glomeruli, have strong affinity for wheat germ agglutinin which reacts with N-acetyl glucosamine. Both of these cell types stained immunocytochemically for fibronectin and actin although the intracellular patterns were somewhat different. These two types of cells are able to secrete extracellular basement membrane material.
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PMID:Cytochemical characterization of cultured adult, guinea pig glomerular cells. 51 6

Starch-activated mouse peritoneal macrophages (STpMAC) plated on plastic demonstrate the adhesive properties typical for activated pMAC: attaching as round cells and, within 15 min, spreading out with marginal membrane ruffles. These attached STpMAC were labeled by lactoperoxidase-catalysed 125I surface iodination, sodium dodecyl-sulfate-lysed, and the lysates electrophoresed on polyacrylamide gels which were examined by autoradiography. The STpMAC morphological phenotype correlates with the labeling of a particular protein (195,000, estimated mol wt). Normal pMAC (NpMAC), from unstimulated mice, do not spread and do not display the 195,000 band. Both pMAC band patterns, including the 195,000 band, are relatively resistant to trypsin digestion, as is pMAC adhesion itself trypsin-resistant. Neither class of pMAC exhibits fibronectin (Cell Adhesion Factor, LETS protein) which is a component in the adhesive matrix of cells forming trypsin-sensitive monolayers. When pMAC are tested against antifibronectin antibody, these cells do not give immunofluorescent staining. In summary, two functions in pMAC adhesion, enzyme resistance and the ability to spread, appear related to molecular properties distinctive for pMAC surface protein.
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PMID:Identification of macrophage external membrane proteins and their possible role in cell adhesion. 70 74

Binding of 125I-labelled fibronectin and vitronectin to streptococci of group A (S. pyogenes), group B (S. agalactiae) and group C (S. dysgalactiae and S. zooepidemicus) isolated from various human infections and bovine mastitis, and S. uberis bovine isolates, was studied. Binding of vitronectin and fibronectin was common among both human groups A and C, and bovine group C streptococci. S. agalactiae strains of human and bovine origin as well as S. uberis bovine isolates bound low levels of both proteins. The binding of radiolabelled fibronectin and vitronectin to selected groups A and C streptococcal strains was specific, time-dependent and occurred with both live and heat-killed (80 degrees C for 15 min) cells. Binding declined rapidly after treatment of cells with trypsin or proteinase K, while pepsin digestion at pH 5.5 affected vitronectin but not fibronectin binding.
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PMID:Comparative studies on binding of vitronectin and fibronectin to groups A and C streptococci. 128 49

A human prostate cancer model was established by inoculating a prostate specific antigen (PSA)-producing LNCaP cell line with either prostate or bone fibroblasts. Alternatively, this human prostate cancer model can also be established by inoculating LNCaP cells with growth factor(s) (GFs) and extracellular matrix (ECM) immobilized on Gelfoam. The resulting LNCaP tumors were used to evaluate PSA production and excretion in athymic hosts. This model was also employed to examine the biochemical nature of mesenchymal cell-derived growth-promoting protein(s) and to assess the efficacy of potential chemotherapeutic agents. Because of the propensity of human prostate cancer to metastasize to the bone, this study defined a 1.0 M NaCl-eluted fraction, MS1, from the conditioned medium of a bone stromal cell line (MS) by heparin-affinity column chromatography. The growth-promoting activity was assayed both in vivo (e.g., tumor formation) and in vitro (e.g., soft agar colony formation). We found that the growth-promoting activity was trypsin- and heat-sensitive, and partially degraded by acid and dithiothreitol. Immunochemical studies indicated that the polyclonal antibody raised against MS1 blocked the growth-promoting effect elicited by the bone-conditioned media. This growth-promoting factor was found to be immunochemically dissimilar to KGF, HGF, and bFGF. However, addition of bFGF, HGF and NGF, but not aFGF, TGF beta, IGF1, IGF2, PDGF, EGF, TGF alpha and KGF, stimulated anchorage-independent growth of prostate cells, a condition closely parallel to tumor formation in vivo. We found that the MS1 fraction also contained fibronectin and tenascin but not laminin or collagen IV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human prostate cancer model: roles of growth factors and extracellular matrices. 128 80

Seeding vascular prostheses with enzymatically harvested endothelial cells can create endothelial linings that improve small-caliber prosthetic patency. But crude bacterial collagenases used for endothelial harvest contain cytotoxic nonspecific proteases and clostridial cell wall debris which might limit their clinical usefulness. We therefore compared the endothelial cell harvest efficiency of crude bacterial collagenase with that of purified bacterial collagenase alone, purified trypsin alone, and combinations of purified bacterial collagenase and trypsin using concentrations of pure collagenase equal in collagenolytic activity to the crude bacterial collagenase material. The efficiency of harvest from human saphenous vein segments was measured by a microtiter well-growth curve assay of the number of living endothelial cells capable of attachment to fibronectin and subsequent growth obtained per unit area of saphenous vein lumen. Whereas pure collagenase and purified trypsin alone both harvested less than 5% of the baseline endothelial cell density on the veins, a combination of purified collagenase and 0.01% w/v purified trypsin was found to harvest 22% +/- 10% (SD) (n = 8 veins) of the approximately 1.3 x 10(5) endothelial cells/cm2 available on normal saphenous veins. This figure was not statistically different from the harvest efficiency of 19% +/- 10% (N = 4 veins) (p greater than 0.05) obtained by use of 0.1% w/v crude collagenase alone. This result suggests that endothelial harvesting can be done with a defined mixture of pure enzymes which would be clinically preferable to presently used crude extracts of clostridial cultures as a standardized preparation for graft seeding.
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PMID:Enzymatic harvesting of adult human saphenous vein endothelial cells: use of a chemically defined combination of two purified enzymes to attain viable cell yields equal to those attained by crude bacterial collagenase preparations. 130 65

In vivo, the extracellular matrix modulates the phenotype of the connective tissue cells both through its biochemical composition and the transfer of mechanical information. In this study, the mechanical effect was investigated in collagen gels populated by skin fibroblasts maintained under tension (bound lattices (BL)) compared with free retracting lattices (FL) and monolayer on plastic. The overall proteins and collagen synthesis of human skin fibroblasts, investigated by isotopic labeling, were decreased respectively by a factor of about 20 and 40 in FL compared with monolayers and increased by a factor of 4 and 6 in BL versus FL. As assayed by the degradation of [3H]collagen type I by trypsin-activated medium conditioned by fibroblasts under the three models of culture, collagenase activity was inversely regulated and increased in lattices when compared with monolayer culture. It was four times higher in FL than in BL. The steady-state level of mRNA coding for procollagen types I, III, and VI polypeptides, fibronectin, elastin, beta-actin, and procollagenase was determined by cDNA hybridization. The mRNA coding for beta-actin as well as for the various extracellular matrix macromolecules were increased in BL when compared with FL while the level of procollagenase mRNA was lower. These data demonstrate the existence of a modulation of the function of the fibroblasts performed by mechanical forces. This regulation operates, at least in part, at a pretranslational level.
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PMID:Pretranslational regulation of extracellular matrix macromolecules and collagenase expression in fibroblasts by mechanical forces. 131 27

We measured the lateral diffusion of the fluorescent lipid analogue dioctadecylindocarbocyanine iodide (DiI) and of membrane glycoproteins labeled with tetramethylrhodamine (TRITC) succinyl concanavalin A (SConA) via fluorescence photobleaching recovery (FPR) at selected times during a temperature downshift experiment on transformation-defective temperature-sensitive (td-ts) Rous sarcoma virus (RSV) NY68-transformed chicken embryo fibroblasts (CEF) and on identically treated CEF and RSV-transformed CEF. There were no significant differences in the lateral diffusion in DiI at any of the times measured. The lateral diffusion of TRITC-SConA on the RSV-transformed CEF, (1.32 +/- 0.12).10(-10) cm2 s-1, was approximately two times faster than that observed in normal CEF, (0.61 +/- 0.06).10(-10) cm2 s-1. In the cells undergoing RSV NY68-mediated transformation, TRITC-SConA diffusion increased over a 24-h period from a value comparable to that observed in normal CEF, (0.72 +/- 0.13).10(-10) cm2 s-1 to a value comparable to the RSV-CEF transformed cells, (1.74 +/- 0.20).10(-10) cm2 s-1. All diffusion measurements reported were made at the permissive temperature for RSV-NY68 (35 degrees C) unless stated otherwise. The changes in the lateral diffusion of TRITC-SConA occurred between the fifth and twelfth hour of the downshift course and could be associated with cytoskeletal disruption and/or fibronectin degradation, both known to occur at this time in RSV-transformed cells. To assess the contribution of extracellular matrix (ECM) degradation, SConA mobility was measured in normal and RSV-transformed cells treated with trypsin. This treatment increased SConA mobility approximately 4-fold in the normal cells relative to untreated controls and only 2-fold in the RSV-CEF transformed cells. No significant difference in SConA mobility between trypsinized spherical normal and transformed cells was apparent.
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PMID:Protein and lipid lateral diffusion in normal and Rous sarcoma virus transformed chick embryo fibroblasts. 131 42

A collection of Haemophilus ducreyi isolates were screened for the ability to bind to fibrinogen, fibronectin, collagen, gelatin and laminin by a particle agglutination test using latex beads coated with the individual proteins. Thirteen of 21 isolates reacted with all five extracellular matrix proteins. Binding of organisms to protein-coated latex beads was inhibited by pretreatment of the bacteria with detergent, trypsin or boiling. Two isolates did not bind to collagen and gelatin with one of these not reacting with laminin either. Seven strains which failed to react with laminin did not express pili when examined by electron microscopy. This observation suggests a specific interaction with the pili of H. ducreyi.
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PMID:Binding of Haemophilus ducreyi to extracellular matrix proteins. 135 80


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