Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular chitinase from marine Alteromonas sp. strain O-7 is unique because of the activation by four major cations contained in sea water, such as Na+, K+, Mg2+, and Ca2+. The positions of S-S bonds of Alteromonas chitinase were identified. Alteromonas chitinase was fragmented by TPCK-trypsin and Staphylococcus aureus V8 protease. The amino acid and sequence analyses of three peptides showed that the positions of disulfide bonds are Cys(94)-Cys(99), Cys(174)-Cys(196), and Cys(386)-Cys(395).
 ...
PMID:Identification of the positions of disulfide bonds of chitinase from a marine bacterium, Alteromonas sp. strain O-7. 853 97

Previous studies have demonstrated that neutrophils possess an active serine protease(s) which may be involved in the process of chemotaxis but the precise identity of this enzyme(s) remains to be determined. In this study fourteen different protease inhibitors were tested over a wide concentration range for their ability to inhibit unstimulated neutrophil movement and chemotaxis to C5a, fMLP and IL-8. Pretreatment of neutrophils with aspartyl or metallo-protease inhibitors had no effect on either chemotaxis or random cell movement. The thiol protease inhibitors E-64 and cystatin, as well as the thiol/serine inhibitors antipain and leupeptin, diminished only C5a-induced chemotaxis. Pretreatment of neutrophils with the serine protease inhibitors PMSF or 3,4-DCI significantly reduced chemotaxis to C5a, fMLP and IL-8. The inhibitor of trypsin-like serine proteases, TLCK, and the neutrophil elastase inhibitor MeO-Suc-AAPV-CMK had no inhibitory effect on cell movement. However, two different inhibitors of chymotrypsin-like serine proteases, TPCK and chymostatin, significantly inhibited movement to any chemoattractant. These results suggest that an active chymotrypsin-like serine protease is essential for neutrophils to respond to chemotactic stimuli.
 ...
PMID:Inhibition of neutrophil chemotaxis by protease inhibitors. Differential effect of inhibitors of serine and thiol proteases. 854 71

The anaerobic bacterium Porphyromonas gingivalis has been implicated as a primary causative agent in adult periodontitis. Several proteinases are produced by this bacterium, and it is suggested that they contribute to virulence and to local tissue injury resulting from infection by P. gingivalis. Cysteine proteinases with specificities to cleave either Arg-X or Lys-X peptide bonds (i.e., gingipains) have been characterized as predominant enzymes associated with vesicles shed from the surface of this bacterium. It has recently been demonstrated that these proteinases are capable of degrading the blood complement component C5, resulting in the generation of biologically active C5a. By using an affinity-purified rabbit antibody raised against residues 9 to 29 of the C5a receptor (C5aR; CD88), we demonstrate that noncysteinyl proteinases associated with vesicles obtained from P. gingivalis cleave the C5aR on human neutrophils. Proteolytic attack of the C5aR by enzymes from the P. gingivalis vesicles was inhibited by TPCK (tolylsullonyl phenylalanyl chloromethyl ketone), PMSF (phenylmethylsulfonyl fluoride), and dichloroisocoumarin, suggesting that serine proteinases are primarily responsible for this degradative activity. The purified vesicle proteinase Lys-gingipain but not Arg-gingipain also cleaved the N-terminal region of the C5aR on the human neutrophils. Lys-gingipain activity was essentially resistant to these inhibitors but was inhibited by TLCK (Nalpha-p-tosyl-L-lysine chloromethyl ketone) and iodoacetamide. A synthetic peptide that mimics the N-terminal region of C5aR (residues 9 to 29; PDYGHY DDKDTLDLNTPVDKT) was readily cleaved by chymotrypsin but not by trypsin, despite the presence of two potential trypsin (i.e., lysyl-X) cleavage sites. The specific sites of cleavage in the C5aR 9-29 peptide were determined by mass spectroscopy for both chymotrypsin and Lys-gingipain digests. This analysis demonstrated that the C5aR peptide is susceptible to cleavage at both potential Lys-gingipain sites (i.e., between residues 17 and 18 [K-D] and 28 and 29 [K-T]) and at two chymotrypsin sites (between residues 14 and 15 [Y-D] and 20 and 21 [L-D]), respectively. These studies suggest that P. gingivalis contains at least two enzymes capable of cleaving the C5aR, Lys-gingipain and a second nontryptic serine proteinase that is distinct from either Arg- or Lys-gingipain.
 ...
PMID:Proteolytic inactivation of the leukocyte C5a receptor by proteinases derived from Porphyromonas gingivalis. 867 97

Rabbit antisera against human myoglobin and horse myoglobin cross-reacted with both myoglobins but only one of them recognized human hemoglobin. Two mouse monoclonal antibodies anti-human myoglobin were obtained, but only one of them (No. 49) cross-reacted with horse myoglobin. Antibody No. 49 and rabbit antibodies reacted also with apo-, FITC- and treated with hydrochloric acid or TPCK-trypsin horse myoglobin, but their binding to myoglobin pretreated with NaOH was reduced. Thirteen peptides overlapping sequence of human myoglobin were synthesized on polyethylene pins. Rabbit and mouse polyclonal antibodies reacted with some of these peptides but no reaction was noted with mouse monoclonal antibodies. Two monoclonal antibodies were applied for specific immunoassay of human myoglobin.
 ...
PMID:Antigenicity of human and horse myoglobins. 887 67

Two neurotoxins, BmK I and BmK II, were purified from the venom of the Chinese scorpion Buthus martensi Karsch. The complete amino acid sequences of both toxins, each containing 64 amino acid residues, were determined by the automatic sequencing of reduced and S-carboxymethylated toxins and their peptides, obtained after cleavage with TPCK-treated trypsin and Staphylococcus aureus V8 protease, respectively. Toxicity as minimum lethal dose tested by i.c.v. injection in mice showed that BmK I was six times more potent than BmK II. Only two amino acid replacements were found: at position 59 Val in BmK I was replaced by Ile in BmK II, and at position 62 a basic Lys residue in BmK I was substituted by a neutral Asn residue in BmK II. These features suggest that the positively charged residue (Lys or Arg) in the C-terminal position 62 (or 61 or 63) may also play an important role in facilitating the interaction between scorpion neurotoxins and the receptor on sodium channels. The effects of BmK I on nerve excitability were examined with the crayfish axon using intracellular recording and voltage-clamp conditions. The results indicate that BmK I preferentially blocks the sodium channel inactivation process. Thus, functional and structural similarities suggest that BmK I and BmK II belong to group 3 of scorpion alpha-type toxins.
 ...
PMID:Two neurotoxins (BmK I and BmK II) from the venom of the scorpion Buthus martensi Karsch: purification, amino acid sequences and assessment of specific activity. 889 91

By immunoprecipitation analysis using antisera against oligo peptides synthesized based on the deduced N-terminal and C-terminal amino acid sequences of the SH proteins of the mumps virus, the SH protein was detected in mumps virus-infected cells. The SH protein expressed from cDNA by the vaccinia-T7 expression system was recovered in the membrane fraction. Association of the SH protein with the membrane was resistant to high salt, EDTA, and alkaline treatment but sensitive to detergents. Indirect immunofluorescence experiments showed that the SH protein is involved in the exocytotic pathway. These data indicate that the SH protein is a membrane protein. Treatment of microsomes with TPCK-trypsin suggested that the SH protein is oriented in the membrane with its C-terminal facing the cytoplasm. Furthermore the SH protein was not detected in a particular strain (Enders strain) of mumps virus, indicating that the mumps virus SH protein is not essential for virus replication.
 ...
PMID:The mumps virus SH protein is a membrane protein and not essential for virus growth. 891 42

3beta-Hydroxysteroid dehydrogenase and steroid Delta5-->4-isomerase (3beta-HSD/isomerase) were purified as a single protein from human term placenta. The affinity alkylator, 5,10-secoestr-4-yne-3,10, 17-trione (secosteroid), was incubated with the purified enzyme (30/1 secosteroid/enzyme molar ratio) to produce an 80% loss of initial isomerase activity over 90 min in a time-dependent, irreversible manner. The secosteroid inactivated 3beta-HSD by only 20% during the same 90 min. Incubations containing the isomerase substrate steroid, 5-androstene-3,17-dione, completely protected the isomerase activity from inactivation by the secosteroid and did not slow the inactivation of 3beta-HSD. The enzyme containing covalently bound steroid was separated from unreacted secosteroid by reversed phase HPLC. Ketones on the protein-bound secosteroid were radiolabeled by reduction with sodium boro[3H]hydride (specific radioactivity 50 microCi/micromol for the transferred tritium). After removal of the unreacted sodium boro[3H]hydride, the affinity-radiolabeled enzyme was digested with trypsin-TPCK, and the peptides were isolated by reversed phase HPLC. The radiolabeled peptide fractions were sequenced. The secosteroid alkylated three tryptic peptides: 251GQFYYISDDTPHQSYDNLNYTLSK274, tritiated His262; 176NGGTLYTCALR186, tritiated Cys183; and 353TVEWVGSLVDR363, tritiated Trp356. Coincubation with the isomerase substrate blocked the labeling of these three peptides and shifted the alkylation by secosteroid to a single tryptic peptide (135EIIQNGHEEEPLENTWPAPYPHSK159, tritiated His142). Using substrate protection to validate specificity, the affinity labeling secosteroid has identified peptides in the enzyme that are associated with isomerase activity.
 ...
PMID:Affinity radiolabeling identifies peptides associated with the isomerase activity of human type I (placental) 3beta-hydroxysteroid dehydrogenase/isomerase. 922 Sep 91

In this study, using zymogram analysis two proteolytic activities were identified in the mouse sarcoma 180 (S-180) cells that were activated by trypsin treatment and inhibited by both BBI and ACTI. These enzymes, with molecular weights of 46 kDa (dominant band) and 62 kDa (minor band), were mainly localized in the cytosol, and had optimal activity at pH 7 and 8 respectively. Their inhibition by DFP, BBI and ACTI but not EDTA and TPCK indicated they were trypsin-like serine proteases and may be the intracellular target-enzymes of protease inhibitors. The level of the precursor of the 62 kDa protease was significantly increased in the S-180 solid and soft tumors, whereas the level of the 46 kDa precursor was almost undetectable, implying that a physiological role may be played by these serine proteases during tumor invasion.
 ...
PMID:Proteolytic activities of mouse sarcoma 180 cells that are inhibited by Bowman-Birk and Kunitz protease inhibitors. 928 64

The complete amino acid sequence of the Rapana thomasiana hemocyanin N-terminal functional unit Rta was determined by direct sequencing and matrix-assisted laser desorption ionization mass spectrometry of the protein and peptides obtained by cleavage with EndoLysC proteinase, TPCK-trypsin and cyanogen bromide. The single polypeptide chain consists of 407 residues. This is the first report on the primary structure of a dioxygen-binding unit from a marine gastropod hemocyanin and of an N-terminal domain from a molluscan dioxygen carrier. Comparison with the sequences of other molluscan hemocyanin functional units shows an average identity of 48 +/- 5 %. Inspection of the Rta sequence revealed residues 27 and 250 as carbohydrate attachment sites. Conclusions about the molecular evolution of the molluscan hemocyanin dioxygen-binding functional units are made.
 ...
PMID:Complete amino acid sequence of dioxygen-binding functional unit of the Rapana thomasiana hemocyanin. 929 21

A novel thermostable protein inhibitor of trypsin and subtilisin, called BN, was isolated from the seeds of Brassica nigra. The purified protein gave a single band on SDS-PAGE, corresponding to a molecular mass of 15 500 +/- 1000 Da. The inhibitor is composed of two disulfide-linked polypeptide chains, consisting of 39 and 90 residues, respectively. The amino acid sequence of the two chains was determined by Edman degradation of peptides, isolated from enzyme hydrolysates with TPCK-trypsin, EndoLysC proteinase and a Glu-specific proteinase of reduced and vinylpyridinated protein samples. A segment of the 'heavy' chain, between residues 65 and 81, showed homology with the reactive site loop region of the 6-kDa trypsin inhibitors from Nicotiana alata. The basic residue in position 39 (N. alata) or 70 (napins) is conserved as arginine or lysine in all inhibitors from N. alata and in all napins hitherto sequenced. Probably, the two families of trypsin inhibitors have structurally similar reactive sites. BN exhibits an extremely high thermostability: CD measurements showed that during heating to 97 degrees C it preserves a considerable part of the polypeptide backbone folding. Studies on the fluorescence properties of the inhibitor BN in the absence and presence of neutral or ionic quenchers demonstrated that the intrinsic emission of this protein is dominated by a tryptophyl residue, buried in the interior of the protein matrix. 20% of the light absorbed by Tyr 63 of the 'heavy' chain is transferred to Trp 26 of the 'light' chain.
 ...
PMID:A novel thermostable inhibitor of trypsin and subtilisin from the seeds of Brassica nigra: amino acid sequence, inhibitory and spectroscopic properties and thermostability. 935 54


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>