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)

A radioimmunological method for determination of human cathodal trypsin-like immunoreactivity is described. DFP-treated human cathodal trypsin is used as standard and tracer. Freshly drawn normal human plasma contains about 25 microgram/l of cathodal trypsin-like immunoreactivity measured as DFP-treated cathodal trypsin. The normally circulating cathodal trypsin-like immunoreactivity is shown to consist mainly of cathodal trypsinogen.
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PMID:Radioimmunological determination and characterization of cathodal trypsin-like immunoreactivity in normal human plasma. 103 94

Further studies on the feedback regulation of pancreatic enzyme secretion by trypsin were conducted in conscious rats, surgically prepared so that pancreatic juice could be collected or returned. Suppression of enzyme secretion by trypsin as well as its stimulation by SBTI occurred only in the upper part of the small intestine, where the hormone CCK is known to be released. Over a limited range, trypsin suppression of pancreatic secretion was proportional to the dose of trypsin. Higher concentrations had no further effect, suggesting "saturation" of the intestine. Trypsin which had its active center blocked by DFP did not suppress enzyme output. These results supported the concept that only trypsin (or chymotrypsin) with an exposed active center suppressed pancreatic enzyme secretion in the rat by somehow suppressing the release of CCK from the intestinal cell. Presumably CCK is released from the intestine following "removal" of trypsin from the intestine either by diverting the juice or by feeding SBTI which binds the enzyme. All of the evidence supported the view that the effect of trypsin or SBTI on pancreatic secretion was mediated at the intestinal level and not in the blood as has been suggested.
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PMID:Factors involved in the intestinal feedback regulation of pancreatic enzyme secretion in the rat. 116 19

Human thrombin (EC 3.4.21.5) binds tightly to p-chlorobenzylamido-epsilon-aminocaproyl agarose, and is not eluted by 2 M NaCl at pH 8. Its zymogen, human prothrombin, does not bind to the same absorbent. 2 M NaCl partially elutes DFP-treated thrombin. For native human and bovine thrombins, protein and activity are quantitatively eluted by 25% dioxane, and upon rechromatography the active human enzyme exhibits the same binding properties. Equally tight binding of human thrombin occurs with derivatives of the m- and p-chlorobenzylamines. With the o-chloro derivative or benzylamine itself insolubilized to epsilon-aminocaproyl agarose, thrombin is eluted by high ionic strength. Bovine trypsin and bovine factor Xa bind less tightly than thrombin to p-chlorobenzylamido-epsilon-aminocaproyl agarose, being eluted by high ionic strength. It is proposed that the specific thrombin adsorption is related to a secondary binding site of high affinity and with hydrophobic properties. This site is not available in the zymogen. Furthermore, the less specific protease, trypsin, and the more specific protease, factor Xa, lack this binding site.
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PMID:High affinity binding of human and bovine thrombins to p-chlorobenzylamido-epsilon-aminocaproyl agarose. 124 92

It has been shown that keratinase--proteinase PIV, the main enzyme of the proteolytic system of S. fradiae, is characterized by high effectiveness in its action on AcAla3OMe--exceeding elastase in catalytic effectiveness several times. This proteinase also cleaves ester and amide bonds formed by the residues of aromatic and basic amino acids, but with a lower effectiveness than chymotrypsin or trypsin. It has also been shown that proteinase IV is a typical serine enzyme highly sensitive to DFP, acting in strongly alkaline pH (about 11.2), with molecular weight 24 kDa and does not contain cysteine.
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PMID:Proteinases of Streptomyces fradiae. III. Catalytic and some physico- chemical properties of keratinolytic proteinase. 128 46

Surface peptidase activities on the human monocytic lineage cell line U937 were characterized. Two diisopropyl phosphofluoridate (DFP)-inhibitable serine peptidases were identified by differences in their hydrolytic activities on chromogenic peptides: one removed tripeptides from the free NH2-terminal end of the synthetic peptide Ala-Ala-Phe-p-nitroanilide (pNA) and was not inhibited by inhibitors of metallo-, cysteic-, and aspartic-proteinases, or by those of elastase-, trypsin- and chymotrypsin-like enzymes, suggesting the presence of a hitherto unidentified serine tripeptidyl endopeptidase; the other peptidase catalyzed the release of Gly-Pro from Gly-Pro-pNA and was inhibited by DFP, phenylmethyl sulfonyl fluoride and diprotin A, thus resembling dipeptidyl peptidase IV (DPP IV) with respect to its substrate specificity and inhibitor profile. A group of N-exo-aminopeptidase activities specifically inhibited by bestatin, was also detected when Ala-, Leu-, Arg- and Lys-pNA were used a substrates. The activities were surface associated and not secreted as determined by extracellular location of product and enzymatic recovery in highly purified U937 cell membranes. Peripheral monocytes and macrophages were found to virtually exhibit identical levels of these two classes of peptidase activities when compared to those detected on U937 cells. The relative contributions of these hydrolytic enzymes to the cleavage of bioactive and radioiodinated cytokines including tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha and interferon-gamma was next examined. The results indicated that N-aminopeptidases do not appear to participate in the catabolism of any tested cytokine. In contrast, the most interesting finding was that both serine peptidases participate in TNF-alpha degradation. Analysis of the final proteolytic digestion products demonstrated the disappearance of the native 17-kDa molecule TNF-alpha, and the concomitant release of biologically inactive fragments of less than or equal to 2 kDa. Together, these observations indicate new roles for both the DPP IV-like enzyme and the tripeptidyl endopeptidase located at the surface of human monocytic cells, including the regulation of the extracellular TNF-alpha concentration. Thus, the identification of functional ectopeptidases provides insight into their potential role in both normal and malignant monocytic function.
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PMID:Human U937 cell surface peptidase activities: characterization and degradative effect on tumor necrosis factor-alpha. 134 32

A high-salt soluble form of acetylcholinesterase (AChE) was purified from monkey (Macaca radiata) whole diaphragm by a two step affinity chromatographic procedure using m-aminophenyl trimethylammonium-chloride hydrochloride-Sepharose and procainamide-Sepharose columns. The purified enzyme showed three major protein bands at 80 kDa, 78 kDa and 60 kDa on SDS-gel electrophoresis. [3H]Diisopropyl fluorophosphate ([3H]DFP) labeled enzyme also gave three radioactive peaks corresponding to these three bands. The purified enzyme pretreated with dithiothreitol and subjected to limited trypsin digestion gave a peptide fragment of molecular weight approximately 300 Da showing weak acetylthiocholine hydrolyzing activity as identified by Sephadex G-25 gel filtration. Sequence analysis showed that the active peptide fragment was a tripeptide with the sequence Ala-Gly-Ser. When the purified AChE was labeled with [3H]DFP, digested with trypsin and subjected to Sephadex G-25 chromatography, a radioactive peak that would correspond to the tripeptide fragment was seen. The kinetics, inhibition characteristics and binding characteristics to lectins of the active peptide fragment was compared with the parent enzyme. A synthetic peptide of sequence Ala-Gly-Ser was also found to exhibit acetylthiocholine hydrolyzing activity. The kinetics and inhibition characteristics of the synthetic peptide was similar to those of the peptide derived from the purified enzyme, except that the synthetic peptide was more specific towards acetylthiocholine than butyrylthiocholine. The specific activity (units/mg) of the synthetic peptide was about 29480 times less than that of the purified AChE.
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PMID:Isolation of a tripeptide (Ala-Gly-Ser) exhibiting weak acetylthiocholine hydrolyzing activity from a high-salt soluble form of monkey diaphragm acetylcholinesterase. 151 18

Acetylcholinesterase was purified from the soluble supernatant of monkey (Macaca radiata) brain basal ganglia by a three-step affinity purification procedure. The purified enzyme showed two major protein bands corresponding to molecular weights of approximately 65 kDa and approximately 58 kDa which could be labelled by [3H]diisopropylfluorophosphate. When the purified enzyme was subjected to limited trypsin digestion followed by gel filtration on Sephadex G-75 or Sephadex G-25 column, a peptide fragment of molecular weight approximately 300 Da having a weak acetylthiocholine hydrolysing activity was isolated. The amino acid sequence analysis of this peptide showed a sequence of Gly-Pro-Ser. When the [3H]DFP labelled enzyme was subjected to limited trypsin digestion and Sephadex G-75 column chromatography, a labelled peptide corresponding to approximately 430 Da was isolated. The kinetics, inhibition characteristics and binding characteristics to lectins of this peptide were compared with the parent enzyme. A synthetic peptide of sequence Gly-Pro-Ser was also found to exhibit acetylthiocholine hydrolysing activity. The kinetics and inhibition characteristics of the synthetic peptide were similar to those of the peptide derived from the purified acetylcholinesterase, except that the synthetic peptide was more specific towards acetylthiocholine than butyrylthiocholine. The specific activity (units/mg) of the synthetic peptide was about 123700 times less than that of the purified AChE.
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PMID:Isolation of a tripeptide showing weak acetylthiocholine hydrolysing activity from a soluble form of monkey basal ganglia acetylcholinesterase by limited trypsin digestion. 187 67

The role of human neutrophil cathepsin G (Cat G) on Eimeria tenella sporozoites was studied in vitro. Sporozoites were incubated for 2 hr at 37 C in PO4 buffer, 0.9% NaCl (PBS), pH 7.6 in the presence of Cat G (50 micrograms/ml), diisopropyl fluorophosphate-inhibited Cat G (DFP-Cat G) (50 micrograms/ml) or PBS alone, prior to being inoculated into embryonated eggs. As judged by oocyst production on day 7 postinoculation, embryo mortality and the hemorrhage scores, both Cat G and DFP-Cat G demonstrated anticoccidial activity; greater activity was obtained with the DFP-Cat G. Sporozoites were exposed also to increasing concentrations of native and trypsin-digested DFP-Cat G (0-100 micrograms/ml) under the same conditions. Significant protection (37% and 49% for native and digested DFP-Cat G, respectively) was obtained with a low concentration (5 mu/ml), and higher concentrations resulted in 70% and 84% protection, respectively. The primary bactericidal domain of Cat G, the HPQYNQR peptide, at 3 concentrations (25, 50, and 100 micrograms/ml), reduced the oocyst production by 46%, 16%, and 15%, respectively. The anticoccidial activity of Cat G may involve a peptide fragment different from the antimicrobial domain of the enzyme.
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PMID:In vitro activity of the human neutrophil cathepsin G on Eimeria tenella sporozoites. 191 28

A strong fibrinolytic enzyme was readily obtained in saline extracts of the earthworm, Lumbricus rubellus. It hydrolyzed not only plasminogen-rich fibrin plates, but also plasminogen-free fibrin plates. The average fibrinolytic activity was about 100 CU (plasmin units) or 250 IU (urokinase units)/g wet weight. The molecular weight and isoelectric point were about 20,000 and 3.4, respectively. The enzyme was heat-stable and displayed a very broad optimal pH range. DFP and SBTI strongly inhibited the enzyme, but the anti-plasmin agent, t-AMCHA, exerted little effect under the same conditions. Purification of the enzyme was performed and three partially purified fractions were obtained. These three fractions were further subdivided. The first fraction (F-I) was divided into three fractions (F-I-0, F-I-1, and F-I-2), which exhibited similar biochemical characteristics. The second fraction (F-II) could not be subdivided. The third fraction (F-III) was divided into two fractions (F-III-1 and F-III-2). Based on results for their enzymatic activities against various substrates, the fraction I enzymes are thought to represent a chymotrypsin-like enzyme and the fraction III enzymes to represent a trypsin-like enzyme. The fraction II enzyme appears to be neither a trypsin- or chymotrypsin-like enzyme nor an elastase. The amino acid compositions of the six enzymes were estimated. Compared with other serine enzymes, these enzymes contained very abundant asparagine or aspartic acid, and there was very little proline or lysine. From the above data, these enzymes are regarded as novel fibrinolytic enzymes, and we name them collectively as Lumbrokinase from the generic name of the earthworm.
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PMID:A novel fibrinolytic enzyme extracted from the earthworm, Lumbricus rubellus. 196 Aug 90

Exposure of bovine pulmonary arterial endothelial cells to 1 mM H2O2 stimulated associated TAME-esterase and PLA2 activities. Pretreatment with the serine esterase inhibitors: PMSF (1 mM), DFP (1 mM), and alpha 1-PI (1 mg/ml) inhibited H2O2-induced stimulation of TAME-esterase and PLA2 activities. The TAME-esterase and PLA2 activities under H2O2 exposure were determined to be linearly correlated. Affinity labelling of the endothelial cell membrane with [3H]DFP demonstrated that the serine esterase resides in a protein having molecular weight of 29,000 daltons (29 kDa) which is similar to that of elastase. Treatment of the endothelial cell homogenate with trypsin (1 microgram/ml) also stimulated PLA2 activity.
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PMID:Involvement of a serine esterase in oxidant-mediated activation of phospholipase A2 in pulmonary endothelium. 201 92


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