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 receptors for aggregated immunoglobulin G (IgG) (an Fc receptor) and for ristocetin-von Willebrand factor on human platelets were studied by means of various modifications of the platelet surface. The expression of these receptors was measured by the agglutination of platelets to ristocetin in the presence of von Willebrand factor, which is part of the factor VIII complex, and by the binding of aggregated IgG coupled to 3H-labelled diazobenzene. Treatment of platelets with chymotrypsin, trypsin, papain and pronase which removed protein and glycoprotein from the platelet under conditions where the release reaction was inhibited caused loss of the expression of the receptor for ristocetin-von Willebrand factor and an enhancement of that for aggregated IgG. Induction of membrane changes with ADP and of the release reaction with the ionophore A23187 abolished agglutination to ristocentin-von Willebrand factor but did not alter the receptor for aggregated IgC. Possible contributions of unspecific membrane changes, produced by protease treatment of platelets, to the modification of receptor expression were eliminated by the use of formaldehyde-treated platelets. Trypsin, papain and pronase destroyed the ability of these platelets to agglutinate to ristocetin-von Willebrand factor but produced no change in the binding of aggregated IgC. Therefore, the receptor for ristocetin-von Willebrand factor is truly sensitive to proteolysis while the Fc receptor is not, but is partially masked by protease-sensitive material.
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PMID:A comparative study of the effect of modification of the surface of human platelets on the receptors for aggregated immunoglobulins and for ristocentin-von Willebrand factor. 31 30

Digestion of bovine colostral whey with trypsin or chymotrypsin caused a progressive loss of the complement-mediated bactericidal activity of naturally-occurring colostral antibodies of E. coli 0111. Bactericidal activity was associated primarily with IgG1 immunoglobulin and to a lesser extent with IgM. Chymotrypsin preferentially attacked IgM, destroying its antibacterial activity and producing an apparent decrease in its mol wt. Trypsin preferentially attacked IgG1, but loss of antibacterial activity was in this case not accompanied by a decrease in molecular weight. Using colostral whey with antiperoxidase activity it was shown that the kinetics of loss of specific antibody activity were similar to those of loss of bactericidal activity. It is therefore suggested that trypsin may cause a loss of specific antibody activity of colostral IgG1 without cleaving the immunoglobulin molecule.
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PMID:The effect of trypsin and chymotrypsin on the bactericidal activity and specific antibody activity of bovine colostrum. 32 42

The adherence of group A streptococci to epithelial cells was studied by using streptococcal strains labeled with [(3)H]uridine or fluorescein isothiocyanate. The ability of the labeled organisms to adhere to Detroit 562 epithelial cells, derived from a human pharyngeal carcinoma, as well as to epithelial cells scraped from the oral cavity was determined. Adherence to monolayer cultures or cell suspensions of Detroit cells compared favorably with adherence to suspensions of human oral epithelial cells. Initial experiments to determine the optimal conditions for adherence showed that adherence was temperature dependent and that the optimal incubation time was 15 min for adherence to epithelial cells in suspension and 30 to 60 min for monolayer cultures. Both streptococci and epithelial cells exhibited specificity in the adherence process. Different streptococcal strains varied in their ability to adhere. Adherence was also affected by the growth stage of the bacterial cultures. Trypsin treatment of the streptococci slightly decreased adherence, whereas hyaluronidase treatment increased the adherence of some strains. Streptococci were found to adhere to only about half of the epithelial cells. Those epithelial cells apparently have a limited number of receptor sites since they can be saturated by adding increasing concentrations of bacteria. Further support for limited receptor sites was provided by competition experiments. Adherence was inhibited by trypsin treatment of the epithelial cells, suggesting that proteins in the epithelial cell membrane may play a role in streptococcal adherence.
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PMID:Adherence of group A streptococci to human epithelial cells. 35 28

Kallikrein was located by the direct immunofluorescence technique to the granule-containing luminal portion of pancreatic acinar cells. For the demonstration of the intracellular distribution of pancreas kallikrein, in vivo fixation of the gland was necessary. No kallikrein was found in the duct cells or in the islets of Langerhans. Quantitation by single radial immunodiffusion showed that the concentration of kallikrein in the presence was 1.32 +/- 51 microgram/g wet weight, i.e. 1/91 that of the rat submandibular gland. Bz-Arg-OEt-esterases were in the pancreas found as pro-enzyme but as active enzyme in the submandibular gland. Trypsin-like esterases, hydrolyzing epsilon-amino caproic acid naphtol-AS-D.HBr (ACA), were found in the active form in both submandibular gland and pancreatic homogenates. The submandibular gland contained per g wet weight 6 times as much ACA-esterase activity as the pancreas. In the submandibular gland, kallikrein and ACA-esterase activity were found together in practically all granular tubular cells. Thus, the granular tubular cell contains kallikrein as well as other trypsin-like enzymes like the ACA-esterase, and is in this way comparable to the pancreatic acinar cell. An extraglandular function of kallikrein is suggested for the pancreas in contrast to other kallikrein-containing exocrine organs.
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PMID:Localization of kallikrein and its relation to other trypsin-like esterases in the rat pancreas. A comparison with the submandibular gland. 36 24

Proteolytic enzymes, protease and trypsin have recently been introduced to reduce the inconsistency hitherto encountered in the unlabelled antibody--enzyme method using PAP. This study investigated factors determining the optimum conditions for use of such enzymes in order to establish which one is most suitable. Trypsin was the most effective enzyme; however, its activity decreased over 3 h, a feature paralleled immunocytochemically. Method and duration of fixation appears to influence the required time of exposure to trypsin in order that consistent immunostaining may be produced. Treatment of sections with trypsin prior to the use of the unlabelled antibody--enzyme method using PAP renders the technique reliable, provided the enzyme is used in a carefully controlled manner.
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PMID:The use of proteolytic enzymes to improve immunoglobulin staining by the PAP technique. 37 7

Trypsin is a prototype of a large group of enzymes belonging to serine proteinases. The X-ray crystal-structure analyses of its proenzyme trypsinogen, of the active trypsin and of their complexes formed with the pancreatic trypsin inhibitor (PTI) have considerably enhanced our understanding of the mechanisms of activitation, action and inhibition. The trypsinogen is an incompletely folded molecule. Its substrate-binding site becomes only completely fixed upon the enzymatic cleavage of an N-terminal peptide. The contact regions of trypsin and PTI are almost complementary. The complex formed is a (stable) intermediate in the normal tryptic substrate-cleavage reaction.
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PMID:[Activation, activity and inhibition of bovine trypsin]. 38 46

Direct comparison of the effector cells mediating natural killer (NK) activity against mouse tumor cells and antibody-dependent cell-mediated cytotoxicity (ADCC) against mouse tumor target cells coated with alloantisera indicated that NK cells and K-cells (effector cells mediating ADCC) may belong to the same subpopulation of lymphocytes, but they have a different mechanism of killing. Effector cells mediating NK activity and ADCC were nonadherent, nonphagocytic Fc receptor-bearing cells that sediment at 3.5-4.5 mm/hour. Treatment with anti-Thy 1.2 serum in the absence of complement resulted in an increase of NK activity, whereas this treatment caused a substantial loss in ADCC. Both NK activity and ADCC were equally sensitive to the in vivo or in vitro effects of X-irridiation. In vivo inoculations of high doses of hydrocortisone resulted in a reduction of NK activity, but ADCC was not affected. NK cells were trypsin-sensitive, with a profound decrease in the cytolytic activity being observed in a 4-hour 51Cr release assay. The activity, however, could be recovered after overnight incubation at 37 degrees C. Trypsin treatment did not inhibit ADCC as measured by the 18-hour assay.
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PMID:Correlation between natural and antibody-dependent cell-mediated cytotoxicity against tumor targets in the mouse. II. Characterization of the effector cells. 38 12

Pronase, trypsin and delta-chymotrypsin deplete rat alveolar peritoneal macrophages of EA (IgG)-binding activity. Trypsin and delta-chymotrypsin show an initially--under certain conditions and lasting--enhancement of receptor activity. Cycloheximide, an inhibitor of protein biosynthesis, accelerated the loss of Fc-receptors and inhibited their reappearance. There are differences between alveolar and peritoneal macrophages in the rate of loss as well as of regeneration of Fc-receptors.
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PMID:Effect of proteinases on EA (IgG)-binding receptors of rat macrophages. 39 42

When the cell wall of Bacillus subtilis is removed by lysozyme and the resultant protoplasts are plated on hypertonic soft agar medium, each protoplast forms an L colony. L bodies from such L colonies again plate as L-colony-forming units (CFU). However, if protoplasts or L bodies are "conditioned" by 1 h of incubation in 0.4% casein hydrolysate medium and then incubated in 25% gelatin medium for 1 h, 60 to 100% of the formerly naked cells give rist to bacillary colonies. The present experiments largely explain the mechanism responsible for the "heritable" persistence of the wall-less state in B. subtilis. It is shown that protoplasts produce a reversion inhibitory factor (RIF) which blocks reversion when the cell concentration exceeds 5 x 105 CFU/ml. This inhibitor is nondialyzable and sensitive to trypsin, heat, and detergent. Efficient reversion at 2 x 107 CFU/ml is obtained if the protoplasts are treated with trypsin after conditioning and chloramphenicol is incorporated into the gelatin reversion medium. In the presence of 500 mug of trypsin per ml, the requirement for gelatin is sharply reduced, and reversion occurs rapidly in liquid medium containing only 10% gelatin. Trypsin also stimulates reversion in L colonies growing on soft agar. Latent RIF is activated by beta-mercaptoethanol. This reagent blocks reversion of protoplast suspensions at densities of 5 x 105 CFU/ml. Comparison of the autolytic behavior of B. subtilis and of the RIF revealed that several or the properties of the two activities coincide: both are inhibited by high concentrations of gelatin, both are activated by beta-mercaptoethanol, and both have high affinity for cell wall. Going on the assumption that RIF is autolysin, models for protoplast reversion is suggested by the finding that mutants with altered teichoic acid show altered reversion behavior.
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PMID:Inhibitory protein controls the reversion of protoplasts and L forms of Bacillus subtilis to the walled state. 40 56

Trypsin inhibitor from sow colostrum was isolated by ion exchange chromatography on DEAE-Sephadex A-50 followed by gel filtration chromatography on Sephadex G-100 and affinity chromatography. Antiserum against sow colostrum trypsin inhibitor was produced by immunization with the purified inhibitor, and made specific by absorption with normal porcine serum. The specific antiserum was used for immunoquantitation by single radial immunodiffusion (SRI). In sow colostrum whey, good agreement was found between the results obtained by SRI and the total trypsin-inhibiting activity as determined by radial diffusion in a casein-containing agarose gel (r = 0.97, n = 10). In sow's milk there was only a very low inhibiting activity, and no colostral inhibitor was demonstrable by SRI. Also in baby-pig urine agreement was found between the two methods (r = 0.97, n = 14). In baby-pig serum such an agreement was not seen, undoubtedly becuase of the presence of genuine serum trypsin inhibitors. By the SRI technique it is possible specifically to determine the colostral inhibitor even in the presence of other trypsin inhibitors.
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PMID:Isolation and immunochemical determination of sow colostrum trypsin inhibitor. 41 13


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