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

---

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

Three vinyl monomers, M-1, M-3, and M-5, in which L-phenylalanine p-nitroanilide was acylated with CH2==CHCONH(CH2)nCO--(n = 1, 3, 5) were synthesized. They were co-polymerized with a large excess of acrylamide (co-polymers PAm-1, PAm-3, and PAm-5) and with a large excess of acrylic acid (co-polymers PAc=1, PAc-3, and PCc-5). In addition, M-5 was co-polymerized with acrylamide containing 2.8 mol % of the hydrophobic monomer N-acrylyl-1-naphthylamine (co-polymer PAm-5N). The rates of the chymotrypsin-catalyzed hydrolysis of the nitroanilide groups of M-5 and the various co-polymers were determined over a range of pH. For some of the systems data were also obtained over a range of substrate concentrations to derive values for Vmax and Km. Results obtained with PAm-5 were found to be independent of the chain length of the co-polymer. At pH 7, 25 degrees and with 2.7 X 10(-6) M enzyme, Vmax values for M-5, PAm-k, PAm-5N, and PAc-5 were 5.5, 5.5, 10, and 3.6 X 10(-8) M/S, while Km values were 8.5, 16.5, 10, and 2.2 X 10(-5),respectively, With PAc-5, the pH activity profile was shifted to higher acidities as compared to the profiles obtained with M-5 and PAm-5. The susceptibility of the co-polymers to chymotrypsin attack decreases sharply with a decreasing spacing of the L-phenylalanine p-nitroanilide residue from the backbone of the polymer chains.
...
PMID:Enzymatic attack on side chains of synthetic polymers. Chymotrypsin-catalyzed hydrolysis of specific substrate groups attached to acrylamide or acrylic acid co-polymers. 0 40

Evidence is presented that N-benzyloxycarbonyl-L-phenylalanine vinyl ester and 1,2-dibromoethyl ester are inhibitors of Walker 256 carcinosarcoma and Ehrlich ascites carcinoma tumor growth. The major effects of these two agents on Ehrlich ascites cell metabolism were the inhibition of deoxyribonucleic acid and protein synthesis and the alteration of cellular regulatory processes controlling cytokinetics. Deoxynucleotide (purine) kinase enzymes appeared to be the focal site for inhibition of deoxyribonucleic acid synthesis with marginal inhibition of thymidylate synthetase activity. Cyclic adenosine monophosphate levels were elevated by drug treatment whereas chromatin protein phosphorylation, cell respiration, and lysosomal activities were inhibited. N-Benzyloxycarbonyl-L-phenylalanine 1,2-dibromoethyl ester was a latent in vitro chymotrypsin inhibitor. Some preliminary evidence suggests that these activated esters may inhibit cellular enzymatic activity by alkylating imidazole and lysine residues of proteins.
...
PMID:Antineoplastic agents III: effects of dibromoethyl and vinyl esters of N-benzyloxycarbonyl-l-phenylalanine on Ehrlich ascites tumor cell metabolism. 72 89

The immobilization of horseradish peroxidase (HRP) onto dissolved agarose by a photochemically initiated graft copolymerization reaction, carried out at room temperature, was studied. Enzyme immobilization parameters such as the catalyst (FeCl3) and the enzyme concentration were considered. Using hexhydro-1,3,5-triacryloyl-s-triazine (HTsT) as vinyl monomer, the agarose/HTsT ratio was the main reaction parameter controlling the copolymer characteristics. By increasing the polymer content of the sample better stability properties were obtained. For the samples with agarose/HTsT ratios of 20/40 and 40/20 (S 20-40, S 40-20) the residual activities after 240 min at 60 degrees C were respectively 47 and 18%. The residual activity in continuous working was 33% for S 40-20 (after 20 h) and 64% for S 20-40 (after 70 h). For both the synthesized copolymers no limitation to substrate diffusion was found but the flexibility of immobilized enzyme decreased with the increase of polymer content as indicated by the Km values that were 0.90 X 10(-4) mol/liter for the sample S 40-20, and 1.50 X 10(-4) mol/liter for the sample S 20-40. Other enzymes (glucose oxidase, alpha-chymotrypsin, and lipoxidase), besides HRP, were immobilized with good yields, showing the wide applicability of the proposed methodology for the preparation of a solid biocatalyst which can be conveniently stored in water suspension or as lyophilized material.
...
PMID:Structure and properties of enzyme graft copolymers: effects of using dissolved agarose on horseradish peroxidase immobilization. 311 94

Penicillin amidase, alpha-chymotrypsin and urease have been immobilized in water-soluble nonstoichiometric polyelectrolyte complexes (N-PEC). N-PEC are formed by modified poly(N-ethyl-4-vinyl-pyridinium bromide) (polycation) and excess poly(methylacrylic acid) (polyanion). N-PEC are a new class of polymers capable, characteristically, of phase transitions solution in equilibrium precipitate induced by slight change in pH or ionic strength. Neither the chemical structure of the carrier nor the number of cross-linkages between an enzyme and a carrier change on phase transition. That gives an unique opportunity to elucidate the difference between enzymes immobilized on water-soluble and water-insoluble supports. A detailed study of the phase transition effect on thermal stability of the enzymes and protein-protein interactions has been carried out. The following effects were found. Pronounced thermal stabilization of penicillin amidase and urease may be achieved on two conditions: the enzyme is in the precipitate; (b) the enzyme is linked to the N-PEC nucleus. Then the thermal stability of N-PEC-bound penicillin amidase increases 7-fold at pH 5.7, 60 degrees C, and 300-fold at pH 3.1, 25 degrees C, compared to the native enzyme. For urease, the thermal stabilization increases 20-fold at pH 5.0, 70 degrees C. The localization of enzyme on N-PEC has been established by titration of alpha-chymotrypsin bound to a polycation or polyanion with basic pancreatic trypsin inhibitor. Both in solution (pH 6.1) and in N-PEC precipitate (pH 5.7), an alpha-chymotrypsin molecule bound to a polyanion is fully exposed to the solution. If the enzyme is bound to a polycation, only 20% of alpha-chymotrypsin molecules in the precipitate and 40% in solution retain their ability for protein-protein interactions. This means that a polycation-bound enzyme is localized in the hydrophobic nucleus of the complex, whereas the polyanion-bound enzyme sits on the hydrophilic shell of the complex. On pH-induced phase transition (pH decreases from 6.1 to 5.7), there occurs a stepwise decrease in penicillin amidase activity which is due to a 9.8-fold increase in the Km for 2-nitro-4-phenylacetamidobenzoic acid. Change of the catalytic activity and thermal stability of N-PEC-bound penicillin amidase is fully reversible and reproducible. Such soluble-insoluble immobilized enzymes with controllable thermal stability and activity may be used for simulating events in vivo and in biotechnology.
...
PMID:Enzymes in polyelectrolyte complexes. The effect of phase transition on thermal stability. 397 68

Immobilization of enzymes (penicillin amidase and alpha-chymotrypsin) in water-soluble nonstoichiometric polyeloctrolyte complexes (PEC) formed by poly(4-vinyl-N-ethylpyridinium bromide) (polycation) and polymethacrylic acid (polyanion) was carried out. Particles of these PEC consist of a nucleus formed by sequences of salt bonds between the units of oppositely charged polyelectrolytes and the hydrophylic shell formed by ionized groups of polyanions which is in excess in PEC. Such a structure of PEC particles results in a cooperative phase transitions of these systems at slight variations of pH and ionic strength. The work demonstrates phase diagrams of PEC solutions. The values of pH and ionic strength at which phase transitions in solutions of different PEC occur were elucidated. The decrease of pH value from 6.1 to 5.7 leads to reversible phase transition followed by a saltatory increase of Km for immobilized penicillin amidase by 5-10 fold depending on substrate used. The phase transition induced by ionic strength increase up to 0,27 M NaCl doesn't change significantly the Km-value of enzymic reaction. The phenomenon observed can be accounted for by the different structure of PEC particles. The catalytic properties of immobilized chymotrypsin were shown to depend on the loci of enzyme attachment. If the enzyme is bound to polyanion, neither conformational changes of the matrix nor phase transition in solution influence its accessibility for the protein inhibitor, but rather change the binding constant. If the enzyme is attached to polycation, i.e. included in the polycomplex nucleus, two fractions of enzymes accessible and inaccessible for protein inhibitor appear.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:[Enzymes incorporated in polyelectrolyte complexes. Effect of matrix conformational changes and phase transitions in solutions on catalytic properties]. 635 18

From poly(vinyl alcohol) precursors, various reactive carriers for the immobilization of enzymes were synthesized. As insoluble starting polymers, the following products were used: poly(vinyl alcohol), gels crosslinked with terephthalaldehyde, hydrolyzed beads of crosslinked poly(vinyl acetate), poly(vinyl acetate-co- ethylene) tubes coated with poly(vinyl alcohol), and poly(vinyl alcohol)-containing synthetic pulp. Reactive groups introduced into these carriers or methods for their activation included the diazonium- and isothiocyanato group, and the glutardialdehyde-, BrCN, 2, 4, 6-trichloro-s-triazien, and p-benzoquinone methods. Furthermore, SH-specific reactive groups such as N-substituted maleimide groups or activated mixed disulfides with 2-thiopyridyl groups could be introduced into PVA-polymers. Enzymes like hydrolases (e.g. papain, trypsin, chymotrypsin, urease), oxidoreductases (e.g. glucose oxydase, catalase, glucose-6-phosphate dehydrogenase) as well as the example of transferase hexokinase coimmobilized with glucose-6-phosphate dehydrogenase, were immobilized by reactive poly(vinyl alcohol) carriers. The properties of the immobilized enzymes were investigated.
...
PMID:Some new reactive polymers for the immobilization of enzymes. 741 95

Enzyme-containing polymeric materials have been developed that have high activity and stability in both aqueous and organic media. These biocatalytic plastics, containing alpha-chymotrypsin and subtilisin Carlsberg, can contain up to 50% (w/w) total protein in plastic materials such as poly(methyl methacrylate, styrene, vinyl acetate, and ethyl vinyl ether). The activation achieved in organic solvents by incorporating proteases in plastic matrices allows for the efficient synthesis of peptides, and sugar and nucleoside esters. The marriage of enzyme technology with polymer chemistry opens up an array of unique applications for plastic enzymes, including active and stable biocatalysts in paints, coatings, resins, foams, and beads, as well as membranes, fibers, and tubings.
...
PMID:Biocatalytic plastics as active and stable materials for biotransformations. 925 96

The multicomponent self-diffusion in nanocapsules and cryogel biocatalytic systems containing alpha-chymotrypsin has been studied with the NMR-PGSE method at various temperatures and compared with the diffusion of such systems without enzyme. Unilamellar vesicles have been formed in water after "coating" with Brij-97 of the poly-(N,N-diallyl-N,N-didodecyl ammonium bromide), poly-DDAB, nanocapsules. The latter have been obtained by UV-irradiation of reversed hydrated micelles from DDAB in cyclohexane. Cryogels were made from poly(vinyl alcohol), PVA, aqueous solutions by a freezing-thawing cyclic process. Both compartmented systems were used as vehicles of the enzyme entrapped in inner aqueous cavities. The activation energies of self-diffusion for both these systems have been calculated. These data contain information concerning morphology and molecular packing. Encapsulation of alpha-chymotrypsin in the poly-DDAB/Brij-97 vesicles and the PVA cryogel lowers the Ds values for all molecules and shifts the cloud point toward the lower temperature. On the contrary, the syneresis point for the PVA cryogel is shifted for 8 degrees toward the higher temperature by the entrapment of the enzyme. Besides, entrapment of alpha-chymotrypsin in the cryogel promotes the increase of the Ea values for the PVA chain on 1.5 kJ/mol below the syneresis point. Such a difference indicates the influence of the H-bond system of PVA hydroxyl groups and water molecules on the interference of the protein globule. Entrapment of alpha-chymotrypsin leads to consolidation of this H-bond system. Copyright 1998 Academic Press.
...
PMID:1H NMR Self-Diffusion in Polymer-Surfactant Nanocapsules and Cryogels with Enzyme. 976 40

The proteasome regulates cellular processes as diverse as cell cycle progression and NF-kappaB activation. In this study, we show that the potent antitumor natural product epoxomicin specifically targets the proteasome. Utilizing biotinylated-epoxomicin as a molecular probe, we demonstrate that epoxomicin covalently binds to the LMP7, X, MECL1, and Z catalytic subunits of the proteasome. Enzymatic analyses with purified bovine erythrocyte proteasome reveal that epoxomicin potently inhibits primarily the chymotrypsin-like activity. The trypsin-like and peptidyl-glutamyl peptide hydrolyzing catalytic activities also are inhibited at 100- and 1,000-fold slower rates, respectively. In contrast to peptide aldehyde proteasome inhibitors, epoxomicin does not inhibit nonproteasomal proteases such trypsin, chymotrypsin, papain, calpain, and cathepsin B at concentrations of up to 50 microM. In addition, epoxomicin is a more potent inhibitor of the chymotrypsin-like activity than lactacystin and the peptide vinyl sulfone NLVS. Epoxomicin also effectively inhibits NF-kappaB activation in vitro and potently blocks in vivo inflammation in the murine ear edema assay. These results thus define epoxomicin as a novel proteasome inhibitor that likely will prove useful in exploring the role of the proteasome in various in vivo and in vitro systems.
...
PMID:Epoxomicin, a potent and selective proteasome inhibitor, exhibits in vivo antiinflammatory activity. 1046 20

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.
...
PMID:New biodegradable hydrogels based on an acryloylated polyaspartamide cross-linked by gamma irradiation. 1057 11


1 2 Next >>

---