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 presence of the enzymatically active allergens equivalent to Der p I (cysteine protease), Der p III (serine protease) and amylase in extracts of Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei was determined using appropriate enzymatic techniques. Biochemical equivalents of all three allergens were present in each extract studied. Studies also showed that the mite extracts contained a variety of other biochemically active enzymes including trypsin, chymotrypsin, carboxypeptidase A and B, glucoamylase and lysozyme. Marked differences in the relative concentrations of some of these enzymes in different mite extracts were observed, particularly trypsin and carboxypeptidase A. The enzymes were physicochemically similar to equivalent enzymes from vertebrate and invertebrate sources. Chromatofocusing studies of faecal extracts derived from D. pteronyssinus and D. farinae showed that several isoforms of each enzyme were present. The data indicated that there were more trypsin isoforms, with pI over a wider range, in extracts prepared from D. pteronyssinus. Proteases and carbohydrases were also found in extracts prepared from faecally enriched material suggesting that they were endoperitrophic and associated with mite digestion. The data suggest that not only are the group I, III and amylase allergens a consistent feature of most pyroglyphid dust mites but also that other proteases and carbohydrases present in mite faeces are allergenic.
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PMID:A comparative study of allergenic and potentially allergenic enzymes from Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei. 128 68

The cleavage of dynorphin and three analogs containing paired basic residues by several proteases was investigated. The cysteine protease of neuroblastoma cells cleaved only the bond between Arg-Arg residues. Submandibular arginyl-endopeptidase, however, cleaved bonds between both Arg-Arg and Arg-Lys residues, and pancreatic trypsin at the carboxyl sides of both arginine and lysine residues. This shows that the cysteine protease is highly specific for paired arginine residues.
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PMID:Dynorphin-degrading cysteine protease is highly specific for paired arginine residues. 134 63

The nucleotide sequence of the genomic RNA1, 7342 nucleotides (nt) of grapevine fanleaf virus strain F13 (GFLV-F13) has been determined from cDNA clones. The complete sequence contained only one long open reading frame (ORF) of 6852 nucleotides extending from nucleotide 243 to 7101. The putative polyprotein encoded by this ORF is 2284 amino acids in length with an Mr of 253K. The location of genome-linked protein and comparison of the primary structure of the 253K polyprotein to that of other closely related viral proteins of the picronavirus-like family allows the proposal of a scheme for the genetic organization of GFLV-F13 RNA1. The primary structure of the polyprotein includes a putative RNA-dependent RNA polymerase of 92K and a cysteine protease of 25K. This protease shares not only major structural homologies, particularly in the substrate-binding pocket, with the trypsin-like serine proteases of other picorna-like viruses, but also their specificity in terms of cleavage. The large region of Mr 133K upstream of the VPg was found to contain at least two domains, one of which could be easily aligned with the NTP-binding sequence pattern and another which may have the characteristics of a protease cofactor. Thus, the 253K protein possesses the same general genetic organization as the corresponding protein of other picorna-like viruses.
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PMID:Complete nucleotide sequence and genetic organization of grapevine fanleaf nepovirus RNA1. 165 53

The previous findings that the group I and III mite allergens, and amylase present in mite faeces are hydrolytic enzymes has prompted a study to determine whether this material contains other enzymes which could be allergenic. Thus, spent growth medium devoid of whole Dermatophagoides pteronyssinus mites was shown to contain glucoamylase, lipase and lysozyme in addition to the cysteine protease, serine protease and amylase activities associated with the above allergens, respectively. All of these enzymes are probably associated with mite digestive processes. They were rapidly solubilised, heterogeneous with regard to charge (pI in the range 4-8) and demonstrated maximum biochemical activity in the neutral pH range. Three serine proteases were detected and comprised a chymotrypsin-like, a trypsin-like and an unclassified enzyme with pI of 4.1 and 5.3, 8.5 and 7.1, respectively. Only one cysteine protease was observed, which paralleled immunochemically identified Der p I in a variety of assays. It was shown to cleave at lysyl residues and could be inhibited by the specific cysteine protease inhibitor, E-64. The remaining serine proteases, glucoamylase, lipase and lysozyme represent potential allergens.
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PMID:Faecally derived hydrolytic enzymes from Dermatophagoides pteronyssinus: physicochemical characterisation of potential allergens. 171 11

A soluble 80-kDa endopeptidase has been isolated from Trypanosoma brucei brucei. The enzyme, which has a pI 5.1, is optimally active at about pH 8.2 and has apparent pKa values of 6.0 and greater than or equal to 10. It is inhibited by the serine protease inhibitor diisopropylfluorophosphate and by the serine protease mechanism-based inhibitor 3,4-dichloroisocoumarin. Unexpectedly, the enzyme is inhibited by the cysteine protease inhibitor benzyloxycarbonyl-Leu-Lys-CHN2 but not by the related diazomethane, butoxycarbonyl-Val-Leu-Gly-Lys-CHN2, nor by other cysteine protease specific compounds. Specificity studies with a variety of amidomethylcoumaryl (AMC) derivatives of small peptides show that the enzyme has a highly restricted trypsin-like specificity. The best substrate, based on the magnitude of kcat/Km, was benzyloxycarbonyl-Arg-Arg-AMC; other good substrates were benzyloxycarbonyl-Phe-Arg-AMC, benzoyl-Arg-AMC, and compounds with Arg at P1 and Ala or Gly at P2. The hydrolysis of most substrates obeyed classical Michaelis-Menton kinetics but several exhibited pronounced substrate inhibition. The enzyme did not activate plasminogen nor decrease blood clotting time; it was inhibited by aprotinin but not by chicken ovomucoid. We conclude that the enzyme is a trypsin-like serine endopeptidase with unusually restricted subsite specificities.
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PMID:Characterization of an endopeptidase of Trypanosoma brucei brucei. 173 36

1. Increases in activities of muscle muticatalytic proteinase, modori-inducing proteinase (latent trypsin-like proteinase), cathepsin B and L-like proteases and cathepsin D were observed more markedly for male fish than female fish, in the spawning stage. 2. Decreases in inhibitory activities of muscle serine and cysteine protease inhibitors were observed more markedly for male fish than female fish in the spawning stage.
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PMID:Effect of maturation on activities of various proteases and protease inhibitors in the muscle of Ayu (Plecoglossus altivelis). 176 22

Human rhinoviruses, like other picornaviruses, encode a cysteine protease (designated 3C) which cleaves mainly at viral Gln-Gly pairs. There are significant areas of homology between picornavirus 3C cysteine proteases and cellular serine proteases (e.g. trypsin), suggesting a functional relationship between their catalytic regions. To test this functional relationship, we made single substitutions in human rhinovirus type 14 protease 3C at seven amino acid positions which are highly conserved in the 3C proteases of animal picornaviruses. Substitutions at either His-40, Asp-85, or Cys-146, equivalent to the trypsin catalytic triad His-57, Asp-102, and Ser-195, respectively, completely abolished 3C proteolytic activity. Single substitutions were also made at either Thr-141, Gly-158, His-160, or Gly-162, which are equivalent to the trypsin specificity pocket region. Only the mutant with a conservative Thr-141 to Ser substitution exhibited proteolytic activity, which was much reduced compared with the parent. These results, together with immunoprecipitation data which indicate that Asp-85, Thr-141, and Cys-146 lie in accessible surface regions, suggest that the catalytic mechanism of picornavirus 3C cysteine proteases is closely related to that of cellular trypsin-like serine proteases.
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PMID:Site-directed mutagenesis suggests close functional relationship between a human rhinovirus 3C cysteine protease and cellular trypsin-like serine proteases. 215 90

The isolation of a metalloproteinase secreted by a rat glioma cell line (BT5C) in serum-free media is described. After affinity purification, the activity was present as a double band with Mr 86000 and 76000 both of which required CaCl2 for activity. The enzyme was able to degrade gelatin but not casein. It was unable to degrade native types I, III, IV and V collagens but their denatured counterparts were degraded. Using a radiolabel release assay the enzyme was inhibited by EDTA, 1:10 phenanthroline and TIMP confirming that it belongs to the family of metalloproteinases. Its activity was not affected by either serine or cysteine protease inhibitors. The proteinase was activated by APMA but was unaffected by trypsin treatment.
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PMID:Isolation and characterization of a metalloproteinase secreted by rat glioma cells in serum-free culture. 224 53

We have isolated and characterized a novel, large, multicatalytic protease from mammalian cells. This protease was designated PABI (protease accumulated by inhibitors). When baby hamster kidney (BHK) cells were grown in medium containing leupeptin, a potent serine-cysteine protease inhibitor, the trypsin-like protease activity (PABI) in the cells increased its level more than 100-fold over the control. This increase was also observed in other cultured cells such as COS, HepG2, and skin fibroblast cells. The activity was also elevated by treatment with other protease inhibitors including chymostatin or trans-epoxysuccinyl-L-leucylamide-(4-guanidino)butane. Immunoblot analysis, by employing antisera prepared against the purified PABI, also showed a concomitant increase of this protein in BHK, COS, and HepG2 cells on leupeptin treatment. PABI was purified to a homogeneous state from leupeptin-treated BHK cells. PABI is a glycoprotein of molecular weight 700,000. PABI was found to be a multimer of a major subunit of apparent Mr of 84,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electron microscopic analysis. PABI dissociates into subunits only under reducing conditions in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PABI has both trypsin-like and chymotrypsin-like protease activities toward synthetic substrates. Both activities were inhibited by phenylmethanesulfonyl fluoride, aprotinin, bovine pancreas trypsin inhibitor, and chymostatin. Leupeptin inhibited only the trypsin-like activity of PABI. p-Chloromercuribenzoate had no effect on either activity. Furthermore, PABI degraded collagen type I and fibronectin. These results indicate that PABI is a novel protease which differs from any known proteases including cytosolic high molecular weight proteases. The physiological function of PABI is yet to be determined.
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PMID:Isolation and characterization of a novel large protease accumulated in mammalian cells in the presence of inhibitors. 267 25

Characterization of the proteases was performed in the crude mite extract fractionated by Sephacryl S-200 gel filtration. Three peaks of protease activities were detected in the fractions. From the results of substrate specificity and susceptibility to the inhibitors, PK.1 protease (about 60 kD) is suggested to be a trypsin-like protease of mites. From the results of susceptibility to various agents, PK.2 (about 30 kD) and PK.3 (about 20 kD) proteases may be cysteine proteases, e.g., papain and cathepsin B. PK.3 protease existed in the precipitate of 60% ammonium sulfate fractionation. The data in the present study suggest the possibility that Dermatophagoides farinae I allergen might be a cysteine protease probably derived from the gastrointestinal tract of the house dust mite.
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PMID:Characterization of the proteases in the crude mite extract. 267 67


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