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 complete amino acid sequence of rat thyrocalcitonin has been determined by automated Edman degradations of the intact molecule, a cyanogen bromide fragment, and by degradations of mixtures of peptides produced by hydrolysis of the hormone with trypsin and chymotrypsin. The sequence determined was H2N-Cys-Gly-Asn-Leu-Ser-Thr-Cys-Met-Leu-Gly-Thr-Tyr-Thr-Gln-Asp-Leu-Asn-Lys-Phe-His-Thr-Phe-Pro-Gln-Thr-Ser-Ile-Gly-Val-Gly-Ala-Pro-NH2. This sequence differs in only two positions from that found in the human hormone, i.e. leucine-16 in the rat vs phenylalanine-16 in the human, and serine-26 in the rat vs alanine-26 in the human. These similarities and differences are consistent with the previously reported immunological properties of the hormones isolated from these two species.
...
PMID:The complete amino-acid sequence of rat thyrocalcitonin. 127 75

The antigenic relatedness of paracrystalline surface array proteins with subunit molecular weights of approximately 52,000 from isolates of Aeromonas hydrophila and Aeromonas veronii biotype sobria belonging to a single heat-stable serogroup was examined. Enzyme-linked immunosorbent assay and immunoblotting with two different polyclonal antisera against surface exposed and non-surface-exposed epitopes of the S-layer protein from A. hydrophila TF7 showed that the S-layer proteins of the mesophilic aeromonads were antigenically diverse. NH2-terminal amino acid sequence analysis of four antigenically different proteins showed that while the proteins were structurally related, they differed in primary sequence. Absorption experiments with heterologous live cells showed that cross-reactive epitopes were in non-surface-exposed regions of the S-layer proteins, while absorption with homologous live cells showed that the immunodominant epitopes of the S-layer protein of strain TF7 were strain specific and exposed on the surface of the native, tetragonal array produced by this strain. Proteolytic digestion of the TF7 S-layer protein with trypsin, chymotrypsin, or endoproteinase Glu-C produced an amino-terminal peptide of approximate Mr 38,000 which was refractile to further proteolytic cleavage under nondenaturing conditions. This peptide carried the immunodominant surface-exposed region of the protein, and chemical cleavage with cyanogen bromide further mapped the portion of these surface-exposed epitopes to a peptide of approximate Mr 26,000, part of which maps within the Mr 38,000 protease-resistant NH2-terminal peptide.
...
PMID:Antigenic diversity of the S-layer proteins from pathogenic strains of Aeromonas hydrophila and Aeromonas veronii biotype sobria. 137 Feb 87

The zeta potential of washed Tice substrain BCG organisms was measured over a range of ionic strengths from I = 0.005 to 0.1 M. No change in the isoelectric point of 3.4-3.7 was evident. Proteolytic enzymes (trypsin/chymotrypsin, pepsin, papain and pronase) and fluorodinitrobenzene abolished the cationic charge, suggesting that this is substantially due to amino groups associated with protein. Neither hot HCI nor cold trichloroacetic acid affected the charge, indicating that ionic groups are not associated with extractable polysaccharides. Methanolysis, treatment with HF and carbodiimide, and cationic detergent (cetyltrimethylammonium bromide) binding indicated that the negative charge was provided by carboxylic acids, phosphoesters and strong acidic groups, possibly sulphates. Standardless quantitative X-ray microanalysis revealed the presence of phosphorus and sulphur on the surface of actively growing BCG colonies.
...
PMID:Origins of BCG surface charge: effect of ionic strength and chemical modifications on zeta potential of Mycobacterium bovis BCG, Tice substrain, cells. 140 39

This paper reports the purification and the properties of a thioredoxin from the fungus Aspergillus nidulans. This thioredoxin is an acidic protein which exhibits an unusual fluorescence emission spectrum, characterized by a high contribution of tyrosine residues. Thioredoxin from A. nidulans cannot serve as a substrate for Escherichia coli thioredoxin reductase. Corn NADP-malate dehydrogenase is activated by this thioredoxin in the presence of dithiothreitol, while fructose-1,6-bisphosphatase is not. The amino acid sequence of Aspergillus thioredoxin was determined by automated Edman degradation after cleavage with trypsin, SV8 protease, chymotrypsin and cyanogen bromide. The masses of tryptic peptides were verified by plasma-desorption mass spectrometry. The mass of the protein was determined by electrospray mass spectrometry and shown to be in agreement with the calculated mass derived from the sequence (M(r) = 11,564). Compared to thioredoxins from other sources, the protein from A. nidulans displays a maximal sequence similarity with that from yeast (45%).
...
PMID:Purification, properties and primary structure of thioredoxin from Aspergillus nidulans. 145 27

A novel class alpha glutathione S-transferase (GST) isozyme is expressed in the hepatic cytosol of rabbits treated with 4-picoline. SDS-PAGE analysis revealed the presence of a new 28-kDa band which cross-reacted with class alpha GST-specific IgG. This new GST isozyme was isolated from the hepatic cytosol of 4-picoline-treated rabbits and purified to homogeneity using S-hexylglutathione-agarose, CM-Sepharose, and PBE118 chromatofocusing chromatography. The isozyme was determined by SDS-PAGE and gel filtration analyses to be a homodimer of approximately 28 kDa with blocked N-terminus. A heterodimer consisting of 25 and 28 kDa subunits with activity toward the substrate 1-chloro-2,4-dinitrobenzene was also purified. Immunoblot analysis revealed that the 25, 26.5, and 28 kDa bands cross-reacted with class alpha GST-specific IgG and failed to react with either class mu or class pi GST-specific antibodies. The 28 kDa enzyme had a pI of 8.2 as determined by nonequilibrium pH gel electrophoresis. The purified 28 kDa enzyme exhibited activity toward 1-chloro-2,4-dinitrobenzene (Km = 1.60 mM and Vmax = 73.5 mumol/min/mg) and cumene hydroperoxide (Km = 1.02 mM and Vmax = 6.92 mumol/min/mg). Amino acid sequence analysis of several fragments resulting from cyanogen bromide cleavage of the 28 kDa GST isozyme revealed a class alpha GST consensus sequence. In addition, proteolytic digestion with alpha-chymotrypsin yielded peptide maps which showed distinct differences between the purified 28 kDa GST and another purified class alpha GST isozyme present in rabbit liver. These results provide evidence that class alpha GST isozymes containing a novel 28 kDa subunit are expressed following treatment with 4-picoline.
...
PMID:Enhanced expression, purification, and characterization of a novel class alpha glutathione S-transferase isozyme appearing in rabbit hepatic cytosol following treatment with 4-picoline. 153 65

A new microheterogeneous non-aqueous medium for enzymatic reactions, based on reversed micelles of a polymeric surfactant, was suggested. The surfactant termed CEPEI, was synthesized by successive alkylation of poly(ethyleneimine) with cetyl bromide and ethyl bromide and was found to be able to solubilize considerable amounts of water in benzene/n-butanol mixtures. The hydrodynamic radius of polymeric-reversed micelles was estimated to be in the range 22-51 nm, depending on the water content of the system, as determined by means of the quasi-elastic laser-light scattering. Polymeric reversed micelles were capable of solubilizing enzymes (alpha-chymotrypsin and laccase) in nonpolar solvents with retention of catalytic activity. Due to the strong buffering properties of CEPEI over a wide pH range, it could maintain any adjusted pH inside hydrated reversed micelles. It was found that catalytic behavior of enzymes entrapped in polymeric reversed micelles was rather insensitive to the pH of the buffer solution introduced into the system as an aqueous component, but determined mostly by acid-base properties of the polymeric surfactant itself. Both catalytic activity and stability of entrapped alpha-chymotrypsin and laccase were found to increase with increasing water content of the system. Under certain conditions, the entrapment of alpha-chymotrypsin into CEPEI reversed micelles resulted in a considerable increase in catalytic activity and stability as compared to aqueous solution. CEPEI reversed micelles were demonstrated to be promising enzyme carriers for use in membrane reactors. Owing to the large dimensions of CEPEI reversed micelles, they are effectively kept back by a semipermeable membrane, thus allowing an easy separation of the reaction product and convenient recovery of the enzyme.
...
PMID:Reversed micelles of polymeric surfactants in nonpolar organic solvents. A new microheterogeneous medium for enzymatic reactions. 160 58

Two arrowhead proteinase inhibitors (inhibitors A and B) were characterized and their primary structures were determined. Both inhibitors A and B are double-headed and multifunctional protease inhibitors. Inhibitor A inhibits an equimolar amount of trypsin and chymotrypsin simultaneously and weakly inhibits kallikrein. Inhibitor B inhibits two molecules of trypsin simultaneously and inhibits kallikrein more strongly than does inhibitor A. The amino acid sequences of inhibitors A and B were determined by sequencing the reduced and S-carboxamidomethylated proteins and their peptides produced by cyanogen bromide or proteolytic lysylendopeptidase or Staphylococcus aureus V8 protease cleavage. Inhibitors A and B consist of 150 amino acid residues with three disulfide bonds (Cys 43-Cys 89, Cys 110-Cys 119, and Cys 112-Cys 115) and share 90% sequence identity, with 13 different residues. Since the primary structures are totally different from those of all other serine protease inhibitors so far known, these inhibitors might be classified into a new protease inhibitor family.
...
PMID:Primary structure and disulfide bridge location of arrowhead double-headed proteinase inhibitors. 161 43

A variety of different peptide-mapping schemes are presented, with emphasis on the development of procedures which can be done with limited quantities (i.e. 5 pmol) of protein. Results are obtained from model proteins which contain disulfide bonds, which must be broken prior to fragmentation of the protein. A reaction involving the simultaneous use of tributylphosphine and 2-methylaziridine to reduce and alkylate the disulfide bonds is employed, due to favorable attributes of these reagents for the scaled-down procedure. The traditional performic acid oxidation reaction to cleave cystine groups is also successfully used with low-picomole quantities of protein. Three different protein digestion reagents are used: trypsin, chymotrypsin, and cyanogen bromide. Each reagent produces a unique mixture of peptides. Capillary electrophoresis is used to separate the peptides, offering high separation efficiencies, short analysis times, and compatibility with small sample sizes. In addition to the conventional use of UV detection for underivatized peptides, laser-induced fluorescence detection is employed in conjunction with an arginine-selective derivatization reaction. This latter procedure for derivatization and detection offers an alternative peptide-mapping mode, in which only the arginine-containing peptides are detected, and is useful in simplifying the peptide maps of large proteins.
...
PMID:Peptide mapping of complex proteins at the low-picomole level with capillary electrophoretic separations. 162 1

Monoamine oxidase B (MAO B) from pig liver has been reported to be a sialoglycoprotein. However, when that enzyme from pig lymphocytes and granulocytes was separated by polyacrylamide gel electrophoresis after labelling with the specific irreversible inhibitor [3H]pargyline, staining with 1-ethyl-2-[3-(1-ethyl-naphtho [1,2d] thiazolin-2-ylidene)-2-methylpropenyl] naphtho [1,2d] thiazolium bromide ("Stains-all") failed to detect the presence of sialic acid residues. Treatment of the enzyme in disrupted lymphocytes and granulocytes, or in mitochondrial fractions prepared from them, with neuraminidase resulted in a decrease in MAO activity. However, after the enzyme was rendered soluble by treatment with octylglucoside, treatment with neuraminidase had no effect on the activity. These results indicate that sialic acid residues are not an intrinsic component of MAO B, although associated material containing such groups appears to affect the activity of the membrane-bound enzyme. The activities of membrane-bound preparations of MAO B from pig lymphocytes and granulocytes were unaffected by treatment with trypsin or beta-chymotrypsin. After the preparations had been rendered soluble by treatment with octylglucoside there was a decrease in the activity on treatment with beta-chymotrypsin, but trypsin treatment had no effect. Thus solubilization resulted in residues sensitive to cleavage by the former enzyme becoming accessible to it. Tryptic and chymotryptic peptides separated from the sodium dodecyl sulphate denatured enzymes by polyacrylamide gel electrophoresis revealed no differences between MAO B prepared from lymphocytes and granulocytes.
...
PMID:Investigations of the possible glycosylation of monoamine oxidase B from pig leucocytes. 167 8

Studies of cGMP binding to both the native cyclic GMP-stimulated phosphodiesterase and to two unique isolated chymotryptic fragments lacking the catalytic domain suggest that the enzyme contains two noncatalytic cGMP-binding sites/homodimer. In the presence of high concentrations of ammonium sulfate, 2 mol of cGMP are bound/mol of cGMP-stimulated phosphodiesterase homodimer. Under these conditions, linear Scatchard plots of binding are obtained that give an apparent Kd of approximately 2 microM. The inclusion of 3-isobutyl-1-methylxanthine produces a curvilinear plot. In the absence of ammonium sulfate, the dissociation of cGMP from the holoenzyme is rapid, having a t1/2 of less than 10 s, and addition of ammonium sulfate to the incubation greatly decreases this rate of dissociation. The native enzyme is resistant to degradation by chymotrypsin in the absence of cGMP; however, in its presence, chymotrypsin treatment produces several discrete fragments. Similarly, in the presence but not in the absence of cGMP, dicyclohexylcarbodiimide causes an irreversible activation of the enzyme without cross-linking the nucleotide to the phosphodiesterase. Both observations provide evidence that a different conformation in the enzyme results from cGMP binding. Only the conformation formed upon cGMP binding is easily attacked by chymotrypsin or permanently activated by treatment with dicyclohexylcarbodiimide. One major chymotryptic cleavage site exposed by cGMP binding is at tyrosine 553, implying that this region takes part in the conformational change. Limited proteolysis experiments indicate that these noncatalytic binding sites are located within a region of internal sequence homology previously proposed to include the cGMP-binding site(s) and that they retain a high affinity and specificity for cGMP independent of the catalytic domain of the enzyme. The products formed by partial proteolysis can be separated into individual catalytically active and cGMP-binding fractions by anion exchange chromatography. Gel filtration and electrophoresis analysis of the isolated fractions suggest that the cGMP-binding peak has a dimeric structure. Moreover, it can be further resolved by polyethyleneimine high performance liquid chromatography into two peaks (Peaks IIIA and IIIB). Peak IIIA binds 2 mol of cGMP/mol of dimer with an apparent Kd of 0.2 microM. Peak IIIB, however, has greatly reduced cGMP binding. Further digestion of these fragments with cyanogen bromide show that the differences between Peaks IIIA and IIIB are due to one or more additional proteolytic nicks in IIIB that remove a few residues near its C terminus, most probably residues 523-550 or 534-550. This in turn suggests that this region is essential for cGMP-binding activity.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Structure and function studies of the cGMP-stimulated phosphodiesterase. 172 Oct 55


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

---