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)

Strains of Streptococcus mutans synthesized bacteriocins in agar plates, but synthesis of detectable bacteriocins in liquid media took place only under certain culture conditions. The composition of the medium proved to be crucial. Trypticase Soy Broth with 4% Yeast Extract meeting the requirements. The effect of the Yeast Extract is obscure, for some strains also formed detectable bacteriocins in a special Trypticase medium without this agent. It was noted that the broth should be filter-sterilized rather than autoclaved and only a few days old. Attempts at liberating cell-bound bacteriocins from washed cells were unsuccessful, even when they were treated with ultrasound, EDTA, or various chemicals followed by ultrasound. On the basis of size and sensitivity to heat the bacteriocins could be divided into two groups, while their resistance to ether and chloroform and to trypsin did not follow this pattern. Dependence on plasmids could not be demonstrated by attempts at curing with acridine orange or ethidium bromide; and the involvement of phages was unlikely, since the inhibition was not transmissible and phage-like structures were not observed in the electron microscope.
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PMID:Synthesis of bacteriocins in liquid cultures of Streptococcus mutans. 26 10

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

Transfer of radioactive materials to fixed cells from an overlying layer of living cells has been examined to determine whether fixed cells can act as acceptors of glycosyltransferases of living cells. After the incubation of living cells were removed by EDTA treatment, and the radioactivity associated with the fixed cells was determined. Lipids, proteins and carbohydrates were found to be transfered from the living cells to the fixed cells. The amount of radioactivity transferred to the fixed cells was dependent on the number of both fixed and living cells and increased with the time of incubation. When fixed cells were treated with chloroform-methanol before the addition of living cells, the transfer of both lipids and proteins to the fixed cells decreased drastically, but only a slight decrease incarbohydrate transfer was observed. Most of the radioactive materials transferred from living cells labeled with glucosamine or fucose to chloroform-methanol-treated fixed cells were solubilized by trypsin but not by the detergents tested. Approximately 55% of the materials transferred from the cells labeled with glucosamine could be solubilized by hyaluronidase and chondroitinase, and the rest was solubilized by neuraminidase and a glycosidase mixture. The treatment of chloroform-methanol-extracted fixed cells with trypsin caused a significant decrease in the transfer from cells labeled with glucosamine. When nucleotide sugars were used as the radioactive precursor, no significant amount of radioactivity was transferred to the fixed cells.
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PMID:Cellular interaction between fixed and living cells. Transfer of radioactive materials from living cells to fixed cells. 37 19

The rectal content of an apparently normal 1-week-old broiler chick yielded an unclassified cytopathogenic virus with cytopathic effects of the round type. It was identified as a picornavirus from the following: ribonucleic acid in the viral core; virus growth in the cytoplasm; a particle about 30 nm in diameter; resistance to ethyl ether, chloroform, trypsin, and acid; relative heat-lability; and partial stabilization to molar magnesium chloride. The virus was stable under freezing and thawing, and sonication. It was distinguished from avian encephalomyelitis virus by the neutralization test.
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PMID:Characterization of a picornavirus isolated from broiler chicks. 39 39

The heterophile antigen (Paul-Bunnell antigen, PBA) of infectious mononucleosis was isolated by extraction of an aqueous suspension of bovine erythrocyte stromata with chloroform-methanol (2:1). The upper aqueous layer contained gangliosides, PBA, and a high-molecular-weight glycoprotein. PBA and gangliosides were separated from the high-molecular-weight glycoprotein by extraction of lyophilized upper layer with chloroform-methanol solvents. Separation of PBA from gangliosides was carried out by chromatography on DEAE-cellulose with chloroform-methanol solvents. PBA appeared to be a minor glycoprotein component of the erythrocyte membrane and had both hydrophobic and hydrophilic properties. It was soluble in either organic or aqueous solvents. On SDS-polyacrylamide gel electrophoresis, it migrated as a single component that stained for protein with Coomassie blue, for carbohydrate with periodic acid-Schiff reagent, and for lipid with oil red 0; it had an apparent molecular weight of 26,000. It was composed of 62% protein with major amino acids; glutamic acid, proline, glycine, isoleucine, leucine, and threonine (158, 116, 98, 90, 85, and 82 residues per 1,000 residues, respectively). Carbohydrate content was 9.2% with major sugar constituents: sialic acid, galactosamine, and galactose. Serologic activity of PBA was destroyed by pronase but not by trypsin.
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PMID:Isolation and partial characterization of the heterophile antigen of infectious mononucleosis from bovine erythrocytes. 40 89

Erythrocytes of different species (chicken, sheep, man, mouse, rat, guinea pig) except rabbit erythrocytes strongly adhere to the marginal zone of mouse spleen follicles in frozen sections. This adherence reaction (AR) is not restricted to red blood cells but is also observed with human lymphocytes. Pretreatment of the tissue sections with trypsin, mercaptoethanol, periodate, chloroform/methanol, acetone, and heating the sections abolishes AR whereas neuraminidase (VCN) treatment of the sections has an amplifying effect. AR is inhibited by preincubation of the neuraminidase- or untreated sections with neuraminic acid (NA). Treatment of the erythrocytes with VCN completely abolishes AR whereas treatment with other enzymes (hyaluronidase, collagenase) is ineffective in this respect. Determination of NA in the erythrocyte membrane before and after VCN treatment reveals a positive correlation between the amount of NA and AR. Rabbit red blood cells have the lowest NA content in their membranes and, in addition, there is little effect of VCN treatment in further reducing it. It is possible that a lectin-like substance is responsible for AR. The biologic significance of AR is hypothetical, but since AR occurs in an area of the spleen playing a role in antigen trapping it is conceivable that this trapping may be mediated by interaction of NA and NA receptor(s).
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PMID:Erythrocyte adherence to the marginal zone of mouse spleen follicle mediated by receptor(s) for neuraminic acid. 46 83

Protease activity in plasma is assayed using 4-methylumbelliferylguanidinobenzoate. The assay is modified by carrying out the reaction in the presence and absence of benzamidine, a competitive inhibitor of trypsin-like proteases. The parameters of the assay are described in detail. Using this assay, our earlier demonstration of a deficiency of protease activity in plasma of patients with cystic fibrosis is confirmed. The activity, corrected for the nonspecific hydrolysis of 4-methylumbelliferylguanidinobenzoate by benzamidine, is expressed as nanomoles of 4-methylumbelliferone released per milliliter plasma. Under standard conditions, the activity in plasma activated with chloroform-ellagic acid was 127.2 +/- 23.1 in 7 controls, 70.4 +/- 11.7 in 11 obligate heterozygotes, and 48.7 +/- 16.6 in 12 patients with cystic fibrosis. Identical results were obtained when unactivated plasma was used. These data demonstrate that the judicious use of specific inhibitors such as benzamidine might be useful in assaying low levels of protease activity in crude systems.
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PMID:Protease deficiency in plasma of patients with cystic fibrosis. Reduced reaction of 4-methylumbelliferylguanidinobenzoate with plasma of patients with cystic fibrosis. 48 55

Seventeen apparently unrelated isolates of Neisseria gonorrhoeae out of 2,123 tested produced a diffusible growth-inhibitory substance against other gonococci. The inhibitor was destroyed by trypsin, not blocked by bovine serum albumin, and not soluble in chloroform-methanol; each isolate was resistant to the inhibitor it produced. Thus, the substance differs from previously described gonococcal inhibitors, and since it fits the description of a bacteriocin we designated it gonocin. The use of gonocin for typing was complicated by the observation that susceptibility to gonocin appears to depend on the gonococcal colony type.
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PMID:Bacteriocin production by Neisseria gonorrhoeae. 82 28

1. The preliminary phytochemical screening of the two seeds established the presence of carbohydrates and/or glycosides, flavnoids, unsaturated sterols and/or triterpenes, saponins, trypsin inhibitors and haemagglutinins. In addition, it established the absence of cardenolides, tannins, alkaloids and oxidase enzyme. 2. Certain pharmacopoeial constants, including moisture, ash, acid-insoluble ash, water-soluble ash and crude fibre were determined. 3. The two seeds were subjected to successive extractions with different organic solvents such as petroleum ether (50-70 degrees C), diethyl ether, chloroform and ethyl alcohol. The successive yields of extractives were determined. Examination of the crude extracts showed that petroleum ether extract contained sterols and/or triterpenes, while ether, chloroform, and ethyl alcohol extracts contained reducing substances. 4. General analysis of the two seeds for proteins, fats, carbohydrates, fibre and ash contents were carried out and the results were given in g/100 g dry seeds. Pigeon pea contained 25.2 g protein, 170 mg calcium and 8.9 mg iron. The protein content of kidney bean was 23 g, while calcium and iron contents were 134 mg and 8.02 mg respectively. 5. Extractions of the proteins using different solvents such as cold water, hot water, saline buffer pH 7 and sodium hydroxide was the best extractant. 6. The amino-acid content of the two seeds, whether raw or cooked, showed that they were deficient in methionine, cystine and tryptophan. Other essential amino acids were present in amounts higher than that given by the FAO provisional pattern. 7. Cooking the seeds by the popular methods used in the country resulted in an increase in the amounts of the amino acids, threonine, leucine and isoleucine, while the other amino acids present remained unchanged or decreased. It was also observed that cooking the seeds destroyed the trypsin inhibitors and haemagglutinins found in the two seeds.
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PMID:Phytochemical and nutritional studies on pigeon pea and kidney bean cultivated in Egypt. 96 10

Different procedures commonly used for extraction, purification, and concentration of staphylococcal enterotoxins from foods were investigated with 131I- and 125I-labeled staphylococcal enterotoxin A. Loss of labeled enterotoxin A was compared with loss of total nitrogen. The results showed that in most of the common procedures, such as gel filtration, ion exchange, and heat treatment, the percentage of loss of labeled enterotoxin A was greater than the loss of total nitrogen. Chloroform extraction and acid precipitation with hydrochloric acid had nearly the same effect on the purification of both labeled enterotoxin A and total nitrogen. Ammonium sulfate precipitation proved to be practical and was successfully used for purification of enterotoxin A from sausage extract. Simultaneous use of trypsin and Pseudomonas peptidase for treatment of food extracts considerably reduced food proteins capable of interfering with serological detection of enterotoxins but did not essentailly influence the loss of enterotoxin A.
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PMID:Comparison of different purification procedure for extraction of staphylococcal enterotoxin A from foods. 98 24


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