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)

The catalytic properties of a sheep mast cell proteinase (SMCP), isolated from abomasal mucosal mast cells, were investigated. The enzyme was shown to have chymotrypsin-like esterase activity, with no detectable amide activity, using a range of low molecular weight substrates. Maximal activity, against Benzyloxycarbonyl-L-tyrosine-4-nitrophenol ester, was determined to be in the range pH 7.6-8.0. Inhibitor studies showed that, unlike chymotrypsin, a serine proteinase, SMCP was found to be susceptible to the action of thiol blocking agents and chelating agents, but to be unaffected by diisopropylphosphofluoridate, a serine proteinase inhibitor.
...
PMID:The catalytic properties of a proteinase isolated from sheep abomasal mucosal mast cells. 353 58

An enzyme which hydrolyzes benzoyl-L-tyrosine ethyl ester (BTEE) was purified from yolk sac membranes of day-18 chick embryos. The purified BTEE hydrolase has a molecular weight of 110,000, being composed of 70,000 and 40,000 subunits, and preferred synthetic substrates for chymotrypsin to those for trypsin. The optimum pH and temperature of this enzyme were 6.5-7.0 and 40 degrees C, respectively. The Km value for BTEE of the enzyme was 16 mM at pH 6.5 and 30 degrees C. The enzyme was inhibited markedly by some chymotrypsin inhibitors but scarcely inhibited by trypsin inhibitors. Magnesium ion acted as potent activator, depending on the enzyme purity and its concentration, whereas p-chloromercuribenzoate and zinc ion inactivated the activity markedly. The BTEE hydrolase was found to hydrolyze proteins such as casein and hemoglobin. These data indicated that the enzyme is a proteinase similar to chymotrypsin. This proteinase could act on yolk proteins, suggesting that it plays an important role in the metabolism of yolk at the yolk sac membrane layer.
...
PMID:Purification and characterization of benzoyl-L-tyrosine ethyl ester hydrolase from the yolk sac membrane of chicken egg. 374 73

Hexyl-alpha-chymotrypsin, a hydrophobic derivative of the enzyme, is explored for the proteinase-catalyzed ester synthesis reaction with N-acetyl-L-tyrosine and ethanol. To guarantee the preservation of the enzyme activity and to allow for the extraction of the product in the organic phase, a biphasic system was used. The Vm increased for the modified enzyme. This phenomenon was linked to the modification of the protein as demonstrated by its chemical denaturation with sodium dodecyl sulfate.
...
PMID:Kinetics of amino acid esterification catalyzed by hydrophobic derivatives of alpha-chymotrypsin. 380 97

We have reported that a serine protease from Pronase, homologous with bovine chymotrypsin, is both active and stable in 6 M guanidinium chloride. The present investigation examined the possibility that this unique property might be used to permit the enzyme to engage in its own purification by cleaving companion proteins to low-molecular-weight products. Analysis with model substrates of the several specific activities that were originally present revealed that only the activity against Nalpha-acetyl-L-tyrosine ethyl ester was demonstrable after incubation for 100 hr in the denaturant. After a moderate loss within the first 24 hr, the remaining activity against this ester was conserved for many days thereafter. Pronase was routinely incubated for 1 week at 22 degrees in 6 M guanidinium chloride at pH 8.0 where the esterases showed maximal activity. Analysis of the products of incubation revealed unexpectedly the presence of two serine proteases that were easily separated. After purification to homogeneity these components proved themselves to be the previously demonstrated subtilisin-like and stable chymotrypsin-like enzymes. The only amino-terminal residue of the chymotrypsin-like enzyme is isoleucine, as it is in the earlier, conventionally purified product. The migration of the single band of this enzyme during acrylamide gel electrophoresis was the same whether purified by the past or present technique. No free amino-terminal group was demonstrable in the subtilisin-like enzyme. This study presents a unique and rapid technique for isolation of these proteases, with the first reported purification to homogeneity of the subtilisin-like component. These enzymes may be useful as probes for local relaxations of conformation in substrate proteins. Furthermore, they may contribute to the preparation of enzyme-free non-protein macromolecules.
...
PMID:Self purification of two serine endopeptidases. 450 75

N-Acetyl-L-tyrosine semicarbazide is hydrolyzed by chymotrypsin (EC 3.4.21.1) to N-acetyl-L-tyrosine and semicarbazide. If a high concentration of semicarbazide is present, the equilibrium for the reaction can be shifted from hydrolysis to synthesis. Using N-acetyl-L-[(13)C]tyrosine enriched at the carboxyl carbon and high concentrations of semicarbazide hydrochloride, we have studied the enzyme-substrate complex of N-acetyl-L-[(13)C]tyrosine semicarbazide and chymotrypsin A(delta) by (13)C nuclear magnetic resonance. We observe no shift within the experimental accuracy of +/-0.05 ppm as the fraction of substrate bound is changed from 0.17 to 0.70. Since E + S right arrow over left arrow ES is in fast exchange on the nuclear magnetic resonance time scale, it is possible to show that when the substrate is bound to the enzyme in the Michaelis complex, the (13)C resonance is shifted less than 0.1 ppm, indicating that negligible substrate strain occurs in this complex at the site of enzymatic attack. These experiments demonstrate the application of nuclear magnetic resonance to the study of particular states along the reaction pathway for enzyme-substrate reactions at equilibrium.
...
PMID:13C high-resolution nuclear magnetic resonance studies of enzyme-substrate reactions at equilibrium. Substrate studies of chymotrypsin-N-acetyltyrosine semicarbazide complexes. 452 21

A colorimetric method to estimate alpha 2-macroglobulin (MG) in human serum is described which is based on the capacity of MG:alpha-chymotrypsin complex to hydrolyze N-acetyl L-tyrosine ethyl ester in the presence of excess crude preparation of a trypsin/chymotrypsin inhibitor from redwood seed. Acetyltyrosine formed was measured using Folin's reagent (7). The method was found to be as reliable as, but at least five times more sensitive than the procedures described using trypsin and soybean trypsin inhibitor. MG level is expressed in terms of micrograms of bovine alpha-chymotrypsin bound. Serum from healthy males had a lower value (150.5 +/- 31.9 micrograms/ml, n = 20) than in females (196.8 +/- 40.4, n = 20). No significant difference between the levels in fasting and postprandial conditions was observed.
...
PMID:Estimation of serum alpha 2-macroglobulin based on the esterolytic activity of bound alpha-chymotrypsin. 608 82

The enzyme activities of four strains of Legionella pneumophilia were investigated by using the API ZYM system (API System S.A., F-38390 Montalieu Vercieu, France) and synthetic substrates. Aminopeptidases were detected specifically against L-alanine, L-arginine, L-aspartic acid, L-cystine, L-glutaminic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-tryptophan, L-tyrosine, and L-valine. Furthermore, the bacteria possesses esterase activity splitting propionate, butyrate, caproate, caprylate, and caprate, but not laurate, myristate, palmitate, and stearate, esters. The enzymes studies were inhibited partially by aprotinin. No inhibition of phosphatase (pH range, 5.4 to 8.5) or of phosphoamidase was observed. Activities of arylsulfatase, chymotrypsin, trypsin, and glycosidases could not be detected.
...
PMID:Enzymatic profile of Legionella pneumophilia. 616 35

Stimulation of rat mast cell suspension from actively sensitized rats with antigen in vitro produced a parallel release of histamine and enzyme, probably proteolytic activity, which releases p-nitrophenol from an L-tyrosine-p-nitrophenyl ester derivative (TPNE). The histamine and enzyme release correlated with respect to their dependence on antigen concentration, reaction time and inhibition by 2,4-DNP and papaverine. In contrast, more than 50% of total histamine but nearly no enzyme was released by the ionophore A 23.187 and C 48/80 (each less than or equal to 1 microgram/ml). The enzyme was apparently secreted predominantly in a particular form. It was approximately 50% inactivated by heating for 1 h at 56 degree C or by incubation for 3 h at 37 degrees C with the chymotrypsin inactivator tosyl-phenylalanine chloromethylketone (TPCK; 2.5 X 10-4 M) or for 5 min at 37 degrees C with benzyl sulphonyl fluoride (2.5 X10-4 M), which reacts with SH groups. Heating for 3 min at 100 degrees C destroyed it completely. On the basis of these properties we suggest that the antigen released enzyme is the known granulabound chymase from rat mast cells. TPNE was not only a cleavable substrate for the enzymatic activity in the 800 g cell supernatant following antigen stimulation, but also a strong inhibitor of the histamine release on administration before antigen (IC50 approximately 10-6 M). It appears that the same enzyme activity acts initially intracellularly as activator of the histamine secretion and then is subsequently released along with histamine as a further mediator. Extracellularly this enzyme may act as a modulator of inflammatory reactions in type I allergy both locally and systemically.
...
PMID:Selective antigen-stimulated release of proteolytic activity from rat mast cells. 616 86

The enzyme spectrum of non proliferating cells of Erysipelothrix rhusiopathiae was investigated by means of different low molecular synthetic substrates. Activities of aminopeptidases were found directed against compounds of L-alanine, L-arginine, L-aspartic acid, glycine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-tryptophane, and L-tyrosine, but not against compounds of l-cystine, L-glutaminic acid, L-histidine, L-hydroxyproline, and L-valine (Table 1). The pH optimum of the investigated aminopeptidases ranges from neutral to alkaline reaction (Table 2). Trypsin, chymotrypsin, or chymotrypsin-like proteases were not detected. E. rhusiopathiae possess esterase activity splitting esters of lower carboxylic acids, i. e. acetic acid, propionic acid, butyric acid, caproic acid, and caprylic acid, but no lipase activity. Under the provoked glycosidases only alpha- and beta-D-galactosidase and glucosaminidase were positive. Weak activities of phosphatases and arylsulfatase were found also (Table 3).
...
PMID:[Investigations of the enzyme spectrum of Erysipelothrix rhusiopathiae (author's transl)]. 627 98

An acidic isozyme of a chymotrypsin-like esteroprotease from the mouse submandibular gland was purified and its properties were compared with those of the basic isozymes purified previously (Takuma, T., et al. (1983) Biochim. Biophys. Acta 755, 70-75), bovine pancreatic alpha-chymotrypsin, and other chymotrypsin-like enzymes of mice. The isoelectric point of the purified enzyme was pH 4.7, and the molecular weight was estimated to be 25,000 by gel filtration on Sephadex G-100. The enzyme hydrolyzed benzoyl-L-tyrosine ethyl ester (Bz-Tyr-OEt) 7 times more slowly than basic isozymes did, but hydrolyzed casein as slowly as the basic isozymes did. The acidic isozyme was 40 times more sensitive to chymostatin than basic isozymes were, but 10 times less sensitive than alpha-chymotrypsin was. Moreover, acidic and basic isozymes were immunologically distinct. Chymotrypsin-like esteroproteases in the submandibular gland were antigenically unique among chymotrypsin-like enzymes in various tissues of mice.
...
PMID:Acidic isozyme of a chymotrypsin-like esteroprotease from mouse submandibular gland. 643 Aug 84


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

---