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)

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.
...
PMID:Pressure effects on enzyme reactions in mainly organic media: alpha-chymotrypsin in reversed micelles of Aerosol OT in octane. 753 34

Conjugates of proteins (bovine serum albumin (BSA) and alpha-chymotrypsin (CHT) with poly(ethylene glycol) and amphiphilic block copolymers of ethylene oxide and propylene oxide (proxanols) were synthesized, using monoaldehyde polymer derivatives as the amino group modifying reagents. Four types of conjugates varying in the placement of hydrophobic block and type of polymer chain distribution were obtained. Methods of purification and characterization of proteins conjugated with proxanols were developed. It was shown that conjugates based on CHT retain high enzymatic activity toward both substrates investigated--N-benzoyl-L-tyrosine and casein-up to high degrees of modification (11 polymer chains per protein molecule). At the same time, CHT--proxanol conjugates were characterized by higher thermostability, the stabilizing effect increasing in parallel with the degree of modification. It was shown that the alteration of sedimentation coefficients of proteins caused by modification was negligible. On the basis of data obtained by the methods of hydrophobic chromatography, sedimentation, and differential scanning calorimetry, conformational models of protein-proxanol conjugates were suggested. It was supposed that conjugates form compact structures in aqueous solutions, which resemble intramolecular micelles, stabilized by hydrophobic interactions between poly(propylene oxide) blocks of proxanols.
...
PMID:Synthesis and physicochemical properties of protein conjugates with water-soluble poly(alkylene oxides). 757 57

The influence of the synthetic substrate (N-acetyl-L-tyrosine ethyl ester) and the different polyols (ethylene glycol, glycerol, erythritol, xylitol and sorbitol) on the thermostability of alpha-chymotrypsin at 60 degrees C have been studied. The results obtained showed an important stabilizing effect in the presence of both additives. In order to describe the kinetics of enzyme stabilization, the experimental results were analyzed by a four-parameters deactivation model with excellent agreement. In all cases, alpha-chymotrypsin exhibited non-first-order deactivation kinetics, corresponding to a two-step unimolecular mechanism, where the main protective effect of polyols was observed in the first-step of the deactivation profile. Thus, the presence of polyols increased the level of activity stabilization (alpha 1), and decreased the first-order deactivation rate constant (k1). Additionally, the experimental results were analyzed as a function of both, the change in the standard free energy of denaturation (delta(delta Gzero)), and a protective effect, defined as the ratio of alpha-chymotrypsin half-lives (with and without polyols), showing in both cases a clear stabilizing effect of these polyhydroxylic cosolvents for the enzyme. The overall protective effect of polyols was also simultaneously related to their concentration and their water-activity depressing power.
...
PMID:Effect of polyols on alpha-chymotrypsin thermostability: a mechanistic analysis of the enzyme stabilization. 776 28

Nucleophilic efficiency of the free amino acids in chymotrypsin-catalyzed acyl transfer in ice at -18 degrees C using ethyl esters of N-maleyl-L-tyrosine and L-tyrosine as the acyl group donors has been studied. Although the amino acids did not act as acyl acceptors in liquid water, the high yields of peptides were obtained in frozen solutions at pH 10.5 (before freezing). The efficiency of amino acids in the formation of the corresponding dipeptides depended on the substrate used, and decreased in the order Ser,Thr,Gln > Lys > Cit > Ala > Ala > Gly > Asn > Arg > Glu > Val > Orn > Asp with no peptide formed with His, Leu, Ile and Pro) for N-maleyl-L-tyrosine ethyl ester and Ser > Lys > Orn > Arg,Cit > Gln > Thr > Asn > Ala > Gly (with no peptide formed with Glu, Val, Asp, His, Leu, Ile and Pro) for L-tyrosine ethyl ester.
...
PMID:Peptide synthesis by chymotrypsin in frozen solutions. Free amino acids as nucleophiles. 835 4

Two 29-residue peptides were prepared, one of which (ChPepz) was designed by surface-simulation synthesis to mimic the active site of alpha-chymotrypsin, and the other (TrPepz), which contained four substitutions relative to ChPepz, was fashioned after the active site of trypsin. Each peptide was cyclized by a disulfide bond. The ChPepz monomer effected hydrolysis of the ester group in N-benzoyl-L-tyrosine ethyl ester, an alpha-chymotrypsin substrate, with Km and kcat values that were comparable to those of alpha-chymotrypsin. ChPepz was completely inactivated by diisopropyl fluorophosphate (DIFP), L-1-p-tosylamino-2-phenylethyl chloromethyl ketone (TPCK), or reduction of the disulfide bond. It had no catalytic activity on N-tosyl-L-arginine methyl ester, a trypsin substrate. On the other hand, TrPepz, which had no effect on N-benzoyl-L-tyrosine ethyl ester, hydrolyzed N-tosyl-L-arginine methyl ester with a Km value that was essentially identical to that of trypsin, but its kcat value was almost half that of trypsin. TrPepz was fully inactivated by reduction of the disulfide bond, by DIFP, or by phenylmethylsulfonyl fluoride but not by TPCK. It was also completely inhibited by soybean trypsin inhibitor, bovine pancreatic trypsin inhibitor, and human alpha 1-antitrypsin. ChPepz and TrPepz hydrolyzed proteins (myoglobin and casein) to give panels of peptides that were similar to those of the same protein obtained with the respective enzyme. However, TrPepz was more efficient than trypsin at hydrolyzing the C bonds of two or more consecutive lysine and/or arginine residues. Like its esterase activity, the proteolytic activity of ChPepz was inhibited by either DIFP or TPCK whereas that of TrPepz was inhibited by either DIFP or phenylmethylsulfonyl fluoride but not by TPCK. Finally, ChPepz and TrPepz were each more active at low temperature than the respective enzyme. This ability to construct fully functional peptide enzymes (pepzymes) of chosen specificities should find many practical applications.
...
PMID:Design of peptide enzymes (pepzymes): surface-simulation synthetic peptides that mimic the chymotrypsin and trypsin active sites exhibit the activity and specificity of the respective enzyme. 818 79

The molecular weights of trypsin and chymotrypsin purified from anchovy viscera were estimated to be 25.6 and 26.1 Kda, respectively, by SDS-PAGE. Both enzymes had their maximal activity at pH 9.0 and 45 degrees C for casein and at pH 8.0 and 45 degrees C for synthetic substrates. Trypsin hydrolyzed at the position of Arg22 and Lys29, and chymotrypsin did at the position of Phe1, Tyr16, Phe24, Phe25, and Tyr26 of insulin beta-chain. The K'm and kcat of trypsin were 50 microM and 1.84 microM-1 min-1 toward N-benzoyl-L-arginine-p-nitroanilide (BAPNA) and those of chymotrypsin were 89 microM and 10.0 microM-1min-1 toward N-succinyl-(Ala)2-Pro-Phe-p-nitroanilide. The activation energy of trypsin and chymotrypsin were estimated to be 14 Kcal/mol toward N-benzoyl-L-arginine-p-nitroanilide and 6.5 Kcal/mol toward benzoyl-L-tyrosine ethyl ester.
...
PMID:Comparison of trypsin and chymotrypsin from the viscera of anchovy, Engraulis japonica. 852 32

A polymerized liposome (PLS) was prepared using a synthesized phosphatidylethanolamine with a diacetylene moiety that showed a reversibly precipitable property on addition and removal of salt. To prepare a soluble-insoluble immobilized enzyme, chymotrypsin was covalently immobilized on the outer surface of the PLS. The carbodiimide method was employed for the enzyme immobilization. Coupling was rapid and nearly complete at a weight ratio of enzyme to the PLS of < 0.12. The immobilized enzyme showed favorable activity yields for both low- and high-mol-wt substrates, i.e., 90 +/- 9% for N-benzoyl-L-tyrosine ethyl ester and 59 +/- 5% for casein up to an enzyme coupling density of 0.38 g/g-PLS. The immobilized enzyme was reusable and more stable at high temperature and long-term incubation than the native enzyme.
...
PMID:Immobilized chymotrypsin on reversibly precipitable polymerized liposome. 898 5

A new method of formation of non-covalent adducts based on an amphiphilic diblock copolymer of ethylene and propylene oxides with molecular mass of 2 kDa and alpha-chymotrypsin (ChT) under high pressure, has been developed. The composition of the complexes corresponds to seven polymer molecules per one ChT molecule in the pressure range of 1.1 to 400 MPa. The complexes fully retain the catalytic activity. Kinetic constants (Km and kcat) for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester catalyzed by the complexes are identical with the corresponding values for native ChT. Analysis of kinetics of thermal inactivation of the complexes revealed that the constant of the rate of the slow inactivation step is markedly lower than for ChT.
...
PMID:[Complex formation between alpha-chymotrypsin and block copolymers based on ethylene and propylene oxide, induced by high pressure]. 901 Dec 41

The South American opossum Didelphis marsupialis is known to be highly resistant to snake envenomation. In this paper it is shown that the opossum serum inhibits haemorrhage induced by both Crotalinae and Viperinae venoms. Tested against Bothrops jararaca (jararaca) venom, the antibothropic complex (ABC) isolated from the opossum serum was at least six times more antihaemorrhagic than the commercial antivenom. ABC showed no proteolytic activity by itself and was not hydrolysed by the venom. It inhibited the hydrolysis of casein by B. jararaca venom, but did not inhibit its hydrolytic activities upon N alpha-benzoyl-L-arginine ethyl ester (BAEE) and N alpha-benzoyl-DL-arginine p-nitroanilide (BAPNA). The inhibitor did not interfere with trypsin and bacterial collagenase activities on BAPNA and N-(3-[2-furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGPA), respectively. It reduced chymotrypsin hydrolysis of N-acetyl-L-tyrosine ethyl ester (ATEE) because ABC is also a substrate for this enzyme. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, B. jararaca venom preferentially degraded fibrinogen A alpha-chain and fibrin alpha-chain. Tested on extracellular matrix proteins, the venom hydrolysed collagen IV, gelatins I and V, laminin and fibronectin, besides depolimerizing collagen I alpha-chain dimers. Fibrillar collagen V was not digested. These hydrolyses were inhibited by ABC and by EDTA. Our results show that the antibothropic complex is a venom metalloproteinase inhibitor, which could, at least partially, account for its antihaemorrhagic activity. Electrophoretic evidence indicated non-covalent complex formation between the antihaemorrhagic factor and component(s) of B. jararaca venom.
...
PMID:Inhibitory properties of the antibothropic complex from the South American opossum (Didelphis marsupialis) serum. 924 80

The precursor or zymogen form of prostate-specific antigen (pro-PSA) is composed of 244 amino acid residues including an amino-terminal propiece of 7 amino acids. Recombinant pro-PSA was expressed in Escherichia coli, isolated from inclusion bodies, refolded, and purified. The zymogen was readily activated by trypsin at a weight ratio of 50:1 to generate PSA, a serine protease that cleaves the chromogenic chymotrypsin substrate 3-carbomethoxypropionyl-L-arginyl-L-prolyl-L-tyrosine-p-nitroanili ne- HCl (S-2586). In this activation, the amino-terminal propiece Ala-Pro-Leu-Ile-Leu-Ser-Arg was released by cleavage at the Arg-Ile peptide bond. The recombinant pro-PSA was also activated by recombinant human glandular kallikrein, another prostate-specific serine protease, as well as by a partially purified protease(s) from seminal plasma. The recombinant PSA was inhibited by alpha1-antichymotrypsin, forming an equimolar complex with a molecular mass of approximately 100 kDa. The recombinant PSA failed to activate single chain urokinase-type plasminogen activator, in contrast to the recombinant hK2, which readily activated single chain urokinase-type plasminogen activator. These results indicate that pro-PSA is converted to an active serine protease by minor proteolysis analogous to the activation of many of the proteases present in blood, pancreas, and other tissues. Furthermore, PSA is probably generated by a cascade system involving a series of precursor proteins. These proteins may interact in a stepwise manner similar to the generation of plasmin during fibrinolysis or thrombin during blood coagulation.
...
PMID:Characterization of the precursor of prostate-specific antigen. Activation by trypsin and by human glandular kallikrein. 926 Nov 79


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

---