Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serine esterases react with [3H]diisopropylphosphofluoridate ([3H]DFP) to produce radioactive adducts that can be resolved by denaturing slab gel electrophoresis. To identify an esterase or its catalytic subunit, a potential substrate was included in the reaction mixture with the expectation that it would suppress the enzyme's reaction with [3H]DFP. The nature of the enzyme could be inferred from the character of the substrates that suppress labeling. The validity of this analytical method was tested with two serine proteases, trypsin and alpha-chymotrypsin, and two serine esterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), and several of their natural or model substrates or inhibitors. Application of the method to complex biological systems was tested with chicken embryo brain microsomes. Trypsin labeling with [3H]DFP was suppressed by alpha-N-benzoyl-l-arginine ethyl ester (BAEE) and poly-l-lysine but not by benzoyl-l-tyrosine ethyl ester (BTEE). [3H]DFP labeling of chymotrypsin was suppressed by both BAEE and BTEE. Labeling of AChE and BuChE was suppressed by their natural and some related substrates and inhibitors. [3H]DFP reacted with brain microsomes to produce nine distinct radioactive bands. When the relevant substrates and inhibitors of AChE were included in the reaction mixtures, labeling of only the 95-kDa band was suppressed, implicating it as AChE. Labeling of the 85- and 79-kDa bands was inhibited by butyrylcholine, suggesting that these proteins have BuChE activity.
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PMID:Identification of serine esterases in tissue homogenates. 1003 48

In this study, using the API-ZYM system, we have reported the enzyme profile of 42 soil strains and 2 clinical strains of Nocardia asteroides isolated locally. Of the 19 enzymes tested, only 7 were demonstrable in over 90% of the soil isolates. These included alkaline phosphatase, esterase lipase, leucine arylamidase, acid phosphatase, phosphohydrolase, alpha-glucosidase and beta-glucosidase. In addition, beta-galactosidase activity was demonstrated in all the strains by the O-nitrophenyl-beta-D-galactopyranoside (ONPG) test. The enzymes which were not demonstrable in > 95% of the strains included valine arylamidase, cystine arylamidase, trypsin, chymotrypsin, alpha-galactosidase, beta-glucoronidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase and alpha-fucosidase. With the exception of valine arylamidase, which was lacking in all but one isolate, the enzyme profiles of the soil isolates were comparable with the clinical isolates of N. asteroides reported in previous studies. The reasons for this difference in the two sets of isolates is not clear. The study reinforces the view that specific differences in the enzymatic profiles of Nocardia species could be used for their rapid identification. However, more extensive studies are needed to establish the reproducibility of this method. To the best of our knowledge, this is the first study of the enzymatic profile of soil isolates of N. asteroides originating from a single geographic region.
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PMID:A study of the enzymatic profile of soil isolates of Nocardia asteroides. 1035 11

alpha,beta-Poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), a synthetic water-soluble biocompatible polymer, was derivatized with glycidyl methacrylate (GMA), in order to introduce in its structure chemical residues having double bonds and ester groups. The obtained copolymer (PHG) contained 29 mol% of GMA residues. PHG aqueous solutions at various concentrations ranging from 30 to 70 mg/ml were exposed to a source of UV rays at lambda 254 nm in the presence or in the absence of N,N'-methylenebisacrylamide (BIS); the formation of compact gel phases was observed beginning from 50 mg/ml. The obtained networks were characterized by FT-IR spectrophotometry and swelling measurements which evidenced the high affinity of PHG hydrogels towards aqueous media at different pH values. In vitro chemical or enzymatic hydrolysis studies suggested that the prepared samples undergo a partial degradation both at pH 1 and pH 10 and after incubation with enzymes such as esterase, pepsin and alpha-chymotrypsin. Finally, the effect of irradiation time on the yield and the properties of these hydrogels was investigated and the sol fractions coming from irradiated samples, properly purified, were characterized by FT-IR and 1H-NMR analyses.
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PMID:New biodegradable hydrogels based on a photocrosslinkable modified polyaspartamide: synthesis and characterization. 1036 57

Biodegradation of poly(urethane)s (PU)s using single enzymes in vitro was assessed by measuring radiolabel release from model poly(ester-urea-urethane) (PESU) and poly(ether-urea-urethane) (PETU) materials synthesized with 14C-labelled monomers. Cholesterol esterase (CE), an enzyme found in monocyte-derived macrophages (MDM), has been reported to cause a significant level of radiolabel release from both of these PUs. Previous work has shown that CE activity could be inhibited by the serine protease/esterase inhibitor, phenylmethylsulfonyl fluoride. Since many serine proteases are present in circulating blood and can be released by cells other than MDM, this study investigated the ability of serine proteases relative to that of CE to cause the degradation of PUs. In addition, the possible role of several oxidative enzymes in the breakdown of PUs was investigated. Proteinase K, chymotrypsin and thrombin, when incubated with PESU, coated on glass slips, caused significant radiolabel release, with proteinase K giving the highest values. However, the highest radiolabel release which proteinase K could elicit was ten times less than CE. Thrombin and then chymotrypsin were progressively worse in their biodegradative activity. Only CE, and not the serine proteases, could elicit a detectable radiolabel release from PETU. Although the release of reactive oxygen species and molecular oxygen occur around an implanted biomaterial, several oxidative systems (peroxidase, xanthine oxidase, catalase), known to produce one or more of these molecular species, were unable to induce radiolabel release from these PUs. The process of biodegradation as assessed by radiolabel release appears to be a specific hydrolytic process, while the role of oxidative enzymes remains less clear.
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PMID:The biodegradation of poly(urethane)s by the esterolytic activity of serine proteases and oxidative enzyme systems. 1042 27

Alpha, beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), a synthetic biocompatible macromolecule, was functionalized with glycidyl methacrylate (GMA) in order to introduce in its side chains residues having double bonds and ester groups. The copolymer (PHG), obtained from PHEA and GMA, had a degree of derivatization of 29 mol%. PHG aqueous solutions are cross-linked by gamma radiation at 0 degrees C either in the presence or absence of N,N'-methylenebisacrylamide (BIS) giving rise to new hydrogel systems. In both cases gelation occurs at quite low doses (0.26 and 0.4 kGy, respectively). The obtained networks were characterized by FT-IR spectrophotometry which confirmed that the cross-linking process involves the vinyl groups of the polymer chains. Swelling measurements evidenced the high affinity of aqueous media at different pH-values towards PHG hydrogels. The sol fractions of the irradiated samples, properly purified, were characterized by FT-IR and 1H-NMR analyses and reduced viscosity measurements. Finally, in vitro chemical or enzymatic hydrolysis studies suggested that the prepared samples undergo a partial degradation at pH 1 and 10 or after incubation with enzymes such as esterase, pepsin, and alpha-chymotrypsin.
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PMID:New biodegradable hydrogels based on an acryloylated polyaspartamide cross-linked by gamma irradiation. 1057 11

Pathologic calcification is thought to be the main cause of failure in the present generation tissue valves fabricated from glutaraldehyde pretreated bovine pericardium (BP). The present investigation describes the in vitro calcification and enzymatic degradation of bovine pericardia after hexamethylene diisocyanate (HMDIC) crosslinking and subsequent modification with polyethylene glycol. The enzymatic degradation of these treated surfaces were monitored by scanning electron micrography and tensile strength measurements. Various proteases, such as alpha-chymotrypsin, bromelain, esterase, trypsin and collagenase were investigated for tissue stability. Incubation of these enzymes with crosslinked pericardia had variably reduced their tensile strength. Among these treated surfaces, polyethylene glycol (PEG) grafted BP via isocyanate functionalities had retained maximum strength. The PEG modified tissues had also indicated a substantial reduction in calcification, when compared to other treated tissues. Further, the biocompatibility of various pericardial tissues were established by platelet adhesion and octane contact angle measurements. It is assumed that the PEG modification of pericardium may interfere with the cellular activation of injury (platelets) to reduce tissue associated calcification. In conclusion, it seems the PEG modification of bovine pericardium via HMDIC may provide new ways of controlling tissue biodegradation and calcification. However, more in vivo studies are needed to develop applications.
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PMID:The anticalcification effect of polyethylene glycol-immobilized on hexamethylene diisocyanate treated pericardium. 1170 61

For (S)-thiirancarboxylic acid a second-order rate constant of k2nd = 222 M(-1) min(-1) for the irreversible inhibition of papain was determined. The ethyl and methyl ester do not inhibit the enzyme time-dependently. An improved synthesis of enantiomerically pure thiirancarboxylic acid is described. It is shown that thiirancarboxylates can be substrates for serine proteases (alpha-chymotrypsin) and esterases (pig liver esterase) and even for metallo proteases (thermolysin).
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PMID:(S)-Thiirancarboxylic acid as a reactive building block for a new class of cysteine protease inhibitors. 1112 43

The synthesis of a novel "reporter group" reagent-3,4-dihydro-3,4,6-trimethyl-2H,8H-pyrano-[3,2g]-1,3-benzoxazin-2,8-dione (DTPBD)-is described. This compound has a cyclic carbamate functionality and thus, like the previously used 3,4-dihydro-3-methyl-6-nitro-2H-1,3-benzoxazin-2-one (DMNB), has the potential to label an esterase such as chymotrypsin. In so doing, DTPBD would incorporate into the protein a covalently linked 4-methylumbelliferone derivative, thus providing a sensitive reporter group that is both chromophoric and fluorescent. Experiments show that DTPBD reacts with chymotrypsin in the predicted manner, except that the labeling process is freely reversible (unlike the case with DMNB). 4-Methylumbelliferyl acetate (which is structurally closely related to DTPBD) is a good substrate for chymotrypsin. The rate of acylation of the enzyme is about an order of magnitude faster than with p-nitrophenyl acetate (which in turn is structurally related to DMNB), an unexpected observation in view of the relative leaving-group abilities of the groups concerned. The results suggest that these various modifiers and substrates show subtle but significant differences in the way they position themselves in chymotrypsin's binding site. Copyright 2000 Academic Press.
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PMID:3,4-Dihydro-3,4,6-trimethyl-2H,8H-pyrano- 1113 46

Dendritic cells from the mesenteric lymph nodes (MLN) contain dense esterase-positive inclusions that may originate in effete intestinal epithelial cells and reach MLN without degradation. The MLN esterases have the electrophoretic mobilities of both intestinal and mononuclear cells. Cryptosporidium parvum (CP)-infected mice have CP Ag-positive cells in MLN and also increased numbers of dense esterase-positive cells, but the CP Ag-positive cells do not stain for esterase. To characterize the handling of epithelial cell products by dendritic cells, we analyzed mRNAs in the MLN of control and CP-infected recombination-activating gene(-/-)DO11.10 mice by oligoarrays. mRNAs for 115 proteins were increased in MLN after CP infection, of which the principal increases in trypsin and chymotrypsin approximated to 250-fold. Colipase, reg-1, C-reactive protein-ductin, and amyloid were also up-regulated >10-fold and all returned to baseline by 28 days after infection. mRNAs for the same proteins were detected in intestinal epithelial cells of infected mice by oligoarrays and RT-PCR after infection. mRNA for CP beta-tubulin was detectable in intestinal epithelial cells between 5 and 18 days after infection but was not detected in the MLN throughout the observation period. It appears that host response to CP infection includes expression of mRNA for some pancreatic enzymes by intestinal epithelial cells and their subsequent transport to the MLN. The esterase and trypsin, and mRNAs for chymotrypsin, colipase, and others that may derive from uninfected epithelial cells, appear to be transported to the MLN intact, while mRNA for CP beta-tubulin that is derived from infected cells is degraded.
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PMID:Intact intestinal mRNAs and intestinal epithelial cell esterase, but not Cryptosporidium parvum, reach mesenteric lymph nodes of infected mice. 1167 48

Aspirin prodrugs have been intensively investigated in an effort to produce compounds with lower gastric toxicity, greater stability or enhanced percutaneous absorption, relative to aspirin. This report describes the hydrolysis kinetics and aspirin release characteristics of isosorbide diaspirinate (ISDA), the aspirin diester of isosorbide. ISDA underwent rapid hydrolysis when incubated in phosphate buffered human plasma solutions (pH 7.4) at 37 degrees C, producing appreciable quantities of aspirin. In 30% human plasma solution the half-life was 1.1 min and 61% aspirin was liberated relative to the initial ester concentration. The hydrolysis kinetics of ISDA were monitored in aqueous solution at 37 degrees C over the pH range 1.03-9.4. The aqueous hydrolysis followed pseudo-first-order kinetics over several half-lives at all pH values, resulting in a U-shaped pH rate profile. Salicylate esters and salicylic acid were formed during these processes. The hydrolysis characteristics of ISDA were also investigated in pH 7.4 phosphate buffered solutions containing alpha-chymotrypsin [EC 3.1.1.1] (t(1/2)=200.9 min), carboxyl esterase [EC 3.1.1.1] (t(1/2)=31.5 min), human serum albumin (t(1/2)=603 min), purified human serum butyrylcholinesterase [EC 3.1.1.8] (80 micro g/ml; t(1/2)=9.4 min; 55% aspirin), purified horse serum butyrylcholinesterase (100 micro g/ml; t(1/2)=1.85 min;11% aspirin) and in 10% human plasma solution in the presence of physostigmine (3 micro M). The results indicate that a specific enzyme present in human plasma, probably human butyrylcholinesterase, catalyses aspirin release from isosorbide diaspirinate.
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PMID:Isosorbide-based aspirin prodrugs. II. Hydrolysis kinetics of isosorbide diaspirinate. 1220 60


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