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)

We studied the influences of inhaled tobacco smoke on lung structure, biochemical changes in bronchoalveolar lavage (BAL) fluid, and glutathione (GSH) content of the lung in the senescence accelerated mouse (SAM), using 30 female SAM-P/8 as the "senescence-prone series", compared with SAM-R/1 as the "senescence-resistant series". At 18 wks of age, half of each series were housed in Hamburg II machines and exposed to an atmosphere of tobacco smoke for 5 wks, 10 min a day, 5 days a wk. At 24 wks of age, all of the animals were sacrificed. Blood, lung, liver, kidney and eyes were removed and the contents of GSH and thiol group (-SH) were measured (n = 5). We also performed BAL, to determine its total protein, albumin, and fibronectin contents, and elastase-like activity, elastase inhibitory capacity (EIC), and trypsin inhibitory capacity (TIC) (n = 5). Histological changes of the lungs from non-lavaged animals were also examined by light microscopy (n = 5). In SAM-P/8 not exposed to tobacco smoke, the mean linear intercept was longer than that in SAM-R/1. The exposure of SAM-P/8 to tobacco smoke caused increases in its lung weight and the ratio of albumin to total protein in BAL fluid, a decrease in the EIC/TIC ratio in BAL fluid, and a decrease in the GSH content and the GSH/-SH ratio of the lung, compared with those not exposed. We also observed focal infiltration of macrophages into alveoli with hyaline membrane and thickened alveolar wall in SAM-P/8 with tobacco exposure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influences of inhaled tobacco smoke on the senescence accelerated mouse (SAM). 228 50

Streptococci of serological groups A, B, C and G displayed different binding activities for plasma proteins. Most of the streptococci studied, except those of group B, bound immunoglobulin G. All streptococci reacted with fibrinogen and, except those of group B, with fibronectin. The majority of streptococci, but none of group B, had an affinity for alpha 2-macroglobulin. Albumin was bound by all cultures of group G and a few of group C. Haptoglobulin interacted with only 1 group A culture. None of the streptococci bound transferrin. The specificity of binding sites for 125I-labelled plasma proteins was revealed in a series of inhibition experiments with the unlabelled proteins. The binding sites on streptococci of group G showed different sensitivities to trypsin and pepsin. Reactivities for immunoglobulin G, however, remained unaffected after treatments of the streptococci with trypsin. Exposure to heat (30 min, 80 degrees C) partially inactivated binding activities for the plasma proteins. Sodium dodecyl-sulphate and acetylimidazole strongly reduced binding of albumin and to a lesser extent that of alpha 2-macroglobulin. They had no or little effect on the interaction with the other plasma proteins. Dioxane decreased almost all binding activities. Ethanol partially diminished the binding of immunoglobulin G, fibrinogen, fibronectin and alpha 2-macroglobulin. Treatments of group G streptococci with guanidine, urea, formamide or methanol-HC1 did not affect their plasma protein binding activities.
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PMID:Interactions of plasma proteins with group A, B, C and G streptococci. 240 15

All 25 cultures of Actinomyces pyogenes tested in the present study bound 125I-labelled human alpha 2-macroglobulin with a mean binding of 65.6%. Thirteen cultures also bound 125I-labelled human haptoglobin with a mean of 51.5%. None interacted with fibrinogen, fibronectin, immunoglobulin G, or albumin. Twenty-eight cultures representing other species of actinomycetaceae did not show any interaction with alpha 2-macroglobulin, haptoglobin, and other plasma proteins tested. The binding of alpha 2-macroglobulin and haptoglobin to A. pyogenes was saturable and could be completely inhibited by the respective unlabelled plasma proteins. The binding of alpha 2-macroglobulin could not be inhibited by unlabelled haptoglobin. On the other hand, alpha 2-macroglobulin blocked the binding of haptoglobin, possibly by steric hindrance. Treatment of the bacteria with trypsin reduced their binding activities for alpha 2-macroglobulin and haptoglobin indicating the protein nature of the binding sites. Exposure to heat (1 h, 80 degrees C) significantly diminished the binding activity for haptoglobin, but not that for alpha 2-macroglobulin. The binding of alpha 2-macroglobulin and haptoglobin could be an important feature in the classification of A. pyogenes among the members of actinomycetaceae.
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PMID:Binding of alpha 2-macroglobulin and haptoglobin to Actinomyces pyogenes. 241 71

The domain structure of human plasma fibronectin was investigated by using heparin-binding and antibody reactivity of fibronectin and its proteolytically derived fragments. Digestion of human plasma fibronectin with a combination of trypsin and cathepsin D produced six major fragments. Affinity chromatography showed that one fragment (Mr 45 000) binds to gelatin and three fragments (Mr 31 000, 36 000, and 61 000) bind to heparin. The 31K fragment corresponds to NH2-terminal fragments isolated from other species. The 36K and 61K fragments are derived from a region near the C-terminus of the molecule and appear to be structurally related as demonstrated by two-dimensional peptide maps. A protease-sensitive fragment (Mr 137 000), which binds neither gelatin nor heparin but which has been shown previously to be chemotactic for cells [Postlethwaite, A. E., Keski-Oja, J., Balian, G., & Kang, A. H. (1981) J. Exp. Med. 153, 494-499], separates the NH2-terminal heparin- and gelatin-binding fragments from the C-terminal 36K and 61K heparin-binding fragments. A monoclonal antibody to fibronectin that recognized the 61K heparin-binding fragment was used to isolate a sixth fragment (Mr 34 000) that did not bind to heparin or gelatin and that represents a difference between the 61K and 36K heparin-binding fragments. Cathepsin D digestion produced an 83K heparin-binding, monoclonal antibody reactive fragment that contains the interchain disulfide bond(s) linking the two fibronectin chains at their C-termini. The data indicate that plasma fibronectin is a heterodimeric molecule consisting of two very similar but not identical chains (A and B). In contrast, enzymatic digestion of cellular fibronectin produced a 50K heparin-binding fragment lacking monoclonal antibody reactivity which suggests that the cellular fibronectin subunit is similar to the plasma A chain in enzyme susceptibility but contains a larger heparin-binding domain. A model relating the differences in the three fibronectin polypeptides to differences in published cDNA sequences is presented.
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PMID:Domain structure of human plasma and cellular fibronectin. Use of a monoclonal antibody and heparin affinity to identify three different subunit chains. 241 23

Epidermal cell culture using microcarriers of Sephadex beads coated with denatured collagen (cytodex 3) was performed. Epidermal basal cells (above 95%) obtained from human skin by trypsinization were cultivated statically on the beads in 96-well culture plates. Proliferation was rapid and great in synchronous waves during 2-7 days after inoculation. The growth rate depended on the inoculation cell population densities. When cells were inoculated at 7.75 X 10(4)/well, the maximum increase was 3.6-fold and at 1.69 X 10(4)/well and 0.32 X 10(4)/well, 2.5-fold and 2.1-fold, respectively. Differentiation was assessed visually on a hemocytometer. The percentage of basal cells of the total cells present in each well was reduced from 98% (on inoculation) to approximately 25% in a week and thereafter. In 1 month after inoculation, cells with keratohyaline-like granules were observed at 12%. The attachment of cells to the beads was rather loose. Cells were supposed to be attached to denatured collagen on the beads via fibronectin contained in the serum of the medium, because denatured collagen had the property to bind strongly to fibronectin. Loose attachment made it possible to harvest intact cells without the use of trypsin. This cell culture system with such new characteristics will be a useful tool for studying epidermal cell biology and biochemistry.
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PMID:Epidermal cell culture using Sephadex beads coated with denatured collagen (cytodex 3). 243 34

Human blood plasma fibronectin decreased slightly the incorporation of precursors into nucleic acids of granulation tissue culture cells. A slight fragmentation of fibronectin, where the fragments with 180-200 kD molecular mass were developed, led to occurrence of the activity 2-fold stimulating the DNA synthesis. After more effective proteolysis using plasmin and trypsin the stimulating effect of fibronectin fragments on synthesis of nucleic acids maintained and constituted 165 +/- 12% and 127 +/- 7% for DNA and RNA, respectively.
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PMID:[Fibronectin fragmentation unmasks the activity stimulating DNA and RNA biosynthesis in granulation tissue cells in vitro]. 243 1

The effects of pulsed electromagnetic fields on the repopulation rate of denuded regions of endothelial cell monolayers and on endothelial cell reorganization into complex vessellike structures was monitored in vitro by using human umbilical vein and bovine aortic endothelial cells. A small (20-40%) but statistically significant enhancement in growth rate of partially denuded endothelial cell monolayers as determined by tritiated thymidine incorporation was observed in the presence of pulsed electromagnetic fields. Morphologically, endothelial cells entering the denuded regions were observed to be elongated, often connecting end to end to form a mycelial or "sprouting" pattern when exposed to pulsed electromagnetic fields. This was in contrast to cells outside of the field which had a more cuboidal morphology. Complete disruption of the endothelial cell monolayer by passaging the cells with EDTA-trypsin resulted in reorganization of some of the cells into three-dimensional vessellike structures after as little as 5-8 hours in the presence of the pulsed electromagnetic field. This reorganization occurred in the presence of heparin, endothelial cell growth factor, and a competent fibronectin matrix. Vascularization for comparable cultures outside of the field did not occur during the time-course of the experiments. Discrete stages of neovascularization were observed in the presence of the field that were qualitatively similar to stages of angiogenesis observed in vivo.
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PMID:Endothelial cell response to pulsed electromagnetic fields: stimulation of growth rate and angiogenesis in vitro. 244 5

In allergic and nonallergic lung diseases, if intraluminal mast cells adhere to airway epithelium, inflammatory mediators released from activated mast cells may reach high local concentrations and thus greatly affect airway function. To determine whether mast cells adhere to airway epithelial cells, radiolabeled or unlabeled dog mastocytoma cells were incubated with cultured dog tracheal epithelial cells, with extracellular matrix substrates, and with cryostat-cut sections of dog trachea. Mast cells adhered well to cultured epithelial cells (35 +/- 13% adhesion, mean +/- 1 SD, n = 23) but adhered poorly to types I and IV collagen or to fibronectin (less than 7.5% mean adhesion in all cases). Similarly, in tracheal tissue sections, mast cells adhered preferentially to epithelial cells in surface epithelium or in submucosal glands but not to basal membrane or connective tissue. Adhesion to cultured epithelial cells was a characteristics of a subpopulation of mast cells, could persist for more than 48 h, did not require energy or the presence of divalent cations, and was not mediated by a known family of leukocyte-associated adhesion glycoproteins. Adhesion was completely abolished by pretreatment of mast cells with pronase E or proteinase K but not with trypsin (up to 10 micrograms/ml at 37 degrees C for 20 min each). In contrast, pretreatment of cultured epithelial cells with any of these proteinases had no effect on adhesion. It is concluded that dog mastocytoma mast cells adhere to dog tracheal epithelial cells and do so selectively. It is suggested that mast cell adhesion to airway epithelium may play a role in the effectiveness of mast cell-epithelial cell interactions, and thus, in certain lung diseases, airway function may be affected by intraluminal mast cells more than is currently appreciated.
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PMID:Selective adhesion of mast cells to tracheal epithelial cells in vitro. 245 Sep 14

Proteolytic enzymes were tested for improving histochemical localization of tissue antigens. Sections, 2-4 micron in thickness, were prepared on sodium-silicate coated slides from formalin-fixed, paraffin-embedded human biopsies. A modification of the Sternberger technique (PAP) and the indirect immunofluorescence method were used for the localization of 15 various antigens: heavy chain immunoglobulins, light chain immunoglobulins, alpha 1-fetoprotein, alpha 1-antichymotrypsin, myoglobin, fibronectin, factor VIII (ass. ag), fibrinogen, lysozyme and cytokeratin. The ability of different proteolytic enzymes (trypsin, pronase, pepsin) to unmask antigen in formalin-fixed sections were tested by variation of concentration, incubation time, temperature and pH. Although proteolytic unmasking to some extent is reliable, good restoration of antigenicity is not always possible. Best results were obtained with pronase E (Serva, FRG).
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PMID:[The proteolytic pretreatment of formalin-fixed tissue in immunohistochemical diagnosis]. 245 12

Baby hamster kidney cells were seeded onto Western blots of fetal serum proteins which had been extracted from several foreign surfaces. This revealed that the major cell adhesive proteins adsorbed onto these surfaces from fetal serum were (1) fibronectin of Mr 220,000 Da and (2) vitronectin of Mr 65,000 and 78,000 Da. Two minor bands of cell attachment were observed at Mr 153,000 and Mr 134,000 Da in the fetal serum proteins extracted from heparin-agarose and serotonin-agarose. However, by exposing the Western blots of separated proteins to a second round of serum proteins, prior to cell blotting, very strong cell adhesive bands were revealed at Mr 153,000, 134,000, and 120,000 Da. By (i) modifying the composition of the serum proteins used to treat the Western blots, (ii) using specific antibodies to fibronectin, and (iii) using radiolabeled fibronectin, it was conclusively demonstrated that the new cell adhesive bands owed their increased cell attachment activity to secondary binding of fibronectin. The new bands were shown (i) to be trypsin sensitive and collagenase sensitive and therefore to be collagen-like proteins and (ii) to react negatively in immunoblots using anti-fibronectin, anti-vitronectin, anti-fibrinogen, anti-fetuin or anti-thrombospondin. In SDS-PAGE (i) the Mr 120,000-Da protein comigrated with the alpha 2-chain of Type I collagen, (ii) the Mr 134,000-Da protein comigrated with the alpha 1-chain of Type I collagen, and (iii) the Mr 153,000-Da protein comigrated with the pN-alpha 1-chain of Type III collagen. Since the novel collagen-like proteins acted as strong sites of cell attachment on nitrocellulose blots by binding fibronectin, they might well promote cell attachment on the foreign surfaces from which they were extracted.
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PMID:Adsorption from fetal calf serum of collagen-like proteins which bind fibronectin and promote cell attachment. 245 51


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