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)

Mechanisms were studied that might explain the attachment and damage to Candida albicans pseudohyphae by neutrophils in the absence of serum. Attachment of neutrophils to pseudo hyphae was inhibited by Candida mannans (1-10 mg/ml), but not by mannose, dextran, chitin, conconavalin A, or highly charged polyamino acids. Contact was also inhibited by pretreatment of Candida before incubation with neutrophils with chymotrypsin, but not trypsin or several inhibitors of proteases. Similar results were obtained with pretreatment of neutrophils, except that trypsin was inhibitory. When pseudohyphae were killed with ultraviolet light, proteinpolysaccharide complexes of mol wt <10,000 were released which appeared to bind to the surfaces of neutrophils and inhibit contact between neutrophils and Candida, as well as other fungi. Damage to Candida by neutrophils was inhibited by agents known to act on neutrophil oxidative microbicidal mechanisms, including sodium cyanide, sodium azide, catalase, superoxide dismutase, and 1, 4 diazobicyclo (2, 2, 2) octane, a singlet oxygen quencher. Neutrophils from a patient with chronic granulomatous disease did not damage Candida at all. However, the hydroxyl radical scavengers mannitol and benzoate were not inhibitory. Cationic proteins and lactoferrin also did not appear to play a major role in this system. Low concentrations of lysozyme which did not damage Candida in isotonic buffer solutions damaged pseudohyphae in distilled water. Isolated neutrophil granules damaged pseudohyphae only with added hydrogen peroxide and halide, and damage occurred only with granule fractions known to contain myeloperoxidase. These findings suggest that neutrophils recognized a molecule on the Candida surface which has a chymotrypsin sensitive protein component, and which may be liberated from the cell surface upon death of organism. The neutrophil receptors for Candida appear to be sensitive to trypsin and chymotrypsin. Damage to Candida by neutrophils occurred primarily by oxidative mechanisms, including the production of superoxide and hydrogen peroxide interacting with myeloperoxidase and halide, as well as singlet oxygen, but did not appear to involve hydroxyl radical. Lysozyme might have an accessory role, under some conditions.
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PMID:Mechanisms of attachment of neutrophils to Candida albicans pseudohyphae in the absence of serum, and of subsequent damage to pseudohyphae by microbicidal processes of neutrophils in vitro. 34 Apr 71

Comparative studies were carried out in the catalytic activity regulation of native alpha-chymotrypsin and its artificially produced hexameric form as an example of non-dissociating oligomeric enzyme (covalently cross-linked by means of succinimidyl-3-(2-pyridylthiopropionate] in the Aerosol OT reversed micelles in octane. Native (monomeric) alpha-chymotrypsin exhibits maximal catalytic activity in the reversed micelles at the hydration degree w0 = 10, when the radius of the micelle inner cavity is equal to the radius of the alpha-chymotrypsin globule. For the alpha-chymotrypsin hexamer, optimum is observed at w0 = 45, with the inner micellar cavity radius (r = 68 A) being approximately equal to the radius of the sphere surrounding the octahedral combination of the six monomeric alpha-chymotrypsin molecules (r = 61 A). Thus, construction of the corresponding oligomeric structures is made easy, with the optimal catalytic activity in a preset range of the hydration degrees.
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PMID:[Artificial oligomerization of enzymes--a new way of regulating their catalytic activity in reversed micellar systems]. 172 69

The phenomenon of regulation of the catalytic activity of enzymes via changing their oligomeric composition in the system of reversed micelles of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in octane was studied using alpha-chymotrypsin (CT) from bovine brain and alkaline phosphatase (AP) from calf intestinal mucosa. The dependences of the enzyme catalytic activity on the AOT hydration degree (Wo = [H2O]/[AOT]), the parameter determining the radius (rc) of the inner cavity of micelles, usually represent the bell-shaped curves. The maximal catalytic activity is observed at such Wo when rc is equal to the size of the enzyme molecule. The position of this maximum strictly correlates with the enzyme oligomeric composition. Thus, in the case of CT this is observed at Wo = 12 when rc is equal to the radius (rp) of the CT globule. In the case of artificially produced conjugate containing six cross-linked CT molecules, this is observed at Wo = 43 when rc is equal to the radius of the sphere surrounding the absolute octahedron composed of six CT globules. The dependence of the catalytic activity of AP on Wo represents a curve with two maxima that are observed when rc is equal to rp of either AP monomer (Wo = 17) or AP dimer (Wo = 25). Ultracentrifugation experiments revealed that variation of Wo causes a change in the oligomeric composition of AP - its transition from monomeric (Wo less than 20) to dimeric form (Wo greater than 20). Hence, the observed maxima correspond to functioning of different oligomeric forms of AP.
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PMID:Regulation of the catalytic activity and oligomeric composition of enzymes in reversed micelles of surfactants in organic solvents. 199 3

The characteristics of water-soluble enzyme (alpha-chymotrypsin) modification with [3H] palmitoyl chloride in the reversed Aerosol OT micelles in octane were determined. The degree of enzyme modification depends on the molar ratio [palmitoyl chloride]/[protein]. The modification reaction is characterized by the wide pH-optimum range and proceeds with high speed.
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PMID:[Effectiveness of acylation of protein amino groups with fatty acid chlorides in a system of reversed micelles of aerosol OT in octane]. 244 19

The research was aimed to establish the equilibrium processes in protein-containing systems of AOT reverse micelles in octane. As chromophore label for tracing the kinetics of the process, the acid-base indicator, p-nitrophenol, was used. The establishing of the equilibrium in the reverse micelle system notably decelerated in the presence of a solubilized protein (native and stearoylated alpha-chymotrypsin). During the establishing of the equilibrium, the solubilized enzyme can be irreversibly inactivated. The level of the residual activity of the enzyme in the equilibrium system depended on the procedure of micellar system preparation. The methods have been offered to set up the equilibrium in the reverse micelle system without inactivation of the solubilized enzyme.
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PMID:[Relaxation phenomena in systems of protein-containing reverse micelles of surfactants in organic solvents]. 245 66

Subtilisin and alpha-chymotrypsin vigorously act as catalysts in a variety of dry organic solvents. Enzymatic transesterifications in organic solvents follow Michaelis-Menten kinetics, and the values of V/Km roughly correlate with solvent's hydrophobicity. The amount of water required by chymotrypsin and subtilisin for catalysis in organic solvents is much less than needed to form a monolayer on its surface. The vastly different catalytic activities of chymotrypsin in various organic solvents are partly due to stripping of the essential water from the enzyme by more hydrophilic solvents and partly due to the solvent directly affecting the enzymatic process. The rate enhancements afforded by chymotrypsin and subtilisin in the transesterification reaction in octane are of the order of 100 billion-fold; covalent modification of the active center of the enzymes by a site-specific reagent renders them catalytically inactive in organic solvents. Upon replacement of water with octane as the reaction medium, the specificity of chymotrypsin toward competitive inhibitors reverses. Both thermal and storage stabilities of chymotrypsin are greatly enhanced in nonaqueous solvents compared to water. The phenomenon of enzymatic catalysis in organic solvents appears to be due to the structural rigidity of proteins in organic solvents resulting in high kinetic barriers that prevent the native-like conformation from unfolding.
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PMID:Enzymatic catalysis in nonaqueous solvents. 327 67

Using ultracentrifugation, the systems of reversed micelles of aerosol OT in octane containing solubilized protein (alpha-chymotrypsin, lysozyme, trypsin, egg albumin, alcohol dehydrogenase from horse liver and gamma-globulin) were studied. The changes in the sedimentation coefficients of reversed micelles during incorporation of the protein are correlated (within a wide range of experimental conditions, e. g. degree of surfactant hydration or protein concentration) exclusively with the molecular weight of the solubilized protein. The simplest solubilization model, according to which the protein molecule is incorporated into the inner cavity of the reversed micelle at the stoichiometric ratio of 1 : 1, which does not affect the external sizes of the reversed micelle, has been proposed. Using alpha-chymotrypsin as an example, the conditions, under which the sedimentation properties of the systems deviate from this model, have been found. These deviations occurred at sufficiently low degrees of the surfactant hydration, when the inner cavity of the reversed micelle is smaller than the effective size of the solubilized protein molecule. In the latter case the protein forms a new micelle of necessary (i. e. larger) size. Since the hydrated micelle can be regarded as an elementary (30-100 A) fragment of biomembranes, the results obtained should be taken into consideration when analyzing the structural organization and functioning of the latter.
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PMID:[Enzymes incorporated into reversed micelles of surfactants in organic solvents. Study of the protein-aerosol OT-H2O-octane system by sedimentation analysis]. 617 48

1. The possibility of stabilizing water-soluble enzymes against the inactivation action of organic solvents by means of surfactants has been studied. Several enzymes (alpha-chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), pyrophosphatase (EC 3.6.1.1), peroxidase (EC 1.11.1.7), lactate dehydrogenase (EC 1.1.1.27) and pyruvate kinase (EC 2.7.1.40)) were used to demonstrate that enzymes can be entrapped into reversed micelles formed by surfactants (Aerosol OT, cetyltrimethylammonium bromide, Brij 56) in an organic solvent (benzene, chloroform, octane, cyclohexane). The enzymes solubilized in this way retain their catalytic activity and substrate specificity. 2. A kinetic theory has been put forward that describes enzymatic reactions occurring in a micelle-solvent pseudobiphasic system. In terms of this theory, an explanation is given for the experimental dependence of the Michaelis-Menten equation parameters on the concentrations of the components of a medium (water, organic solvent, surfactant) and also on the combination of the signs of charges in the substrate molecule and on interphase (++, +-, --). 3. The results obtained by us may prove important for applications of enzymes in organic synthesis and for studying the state and role of water in the structure of biomembranes and active centres of enzymes.
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PMID:The principles of enzyme stabilization. VI. Catalysis by water-soluble enzymes entrapped into reversed micelles of surfactants in organic solvents. 721 47

Biocatalytic transformations in reversed micelles formed by anionic surfactant Aerosol OT in octane have been studied at high pressures by an example of alpha-chymotrypsin-catalyzed hydrolysis of N-carbobenzoxy-L-tyrosine p-nitrophenyl ester and N-succinyl-L-phenylalanine p-nitroanilide. For the first time it has been found that the enzyme retains high activity in these water-in-oil microemulsions up to a pressure of 2 kbar. The value of the activation volume (delta V*) for the enzyme reactions shows a dependence on the water content in the system. When the size of the micellar aqueous inner cavity (as evaluated at 1 atm) approaches the molecular size of alpha-chymotrypsin, delta V* becomes significantly different from the value in aqueous solution and in the micelles with a larger size. Possibilities of regulating the enzyme activity by pressure in systems with a low content of water are discussed.
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PMID:Pressure effects on enzyme reactions in mainly organic media: alpha-chymotrypsin in reversed micelles of Aerosol OT in octane. 753 34

Using the system of reversed micelles of Aerosol OT1 in octane as an instrument revealing the possibility of supramolecular structures formation, we have shown that the native alpha-chymotrypsin can form complexes with glycoproteins. Dimers of the native alpha-chymotrypsin with the artificially glycosylated one and with horseradish peroxidase (natural glycoprotein) were obtained. The position of the optimum on the dependence of the catalytic activity upon the hydration degree confirms the compact organization of the formed complexes. The ability of alpha-chymotrypsin to form such kind of complexes seems to play a key role in its absorption on glycocalix in vivo.
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PMID:Lectin-like center in the molecule of alpha-chymotrypsin: formation of complexes with peroxidase and artificially glycosylated alpha-chymotrypsin. 766 20


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