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 interaction of alpha-chymotrypsin, invertase, alcohol dehydrogenase and alkaline phosphatase with some ionic and non-ionic surfactants, viz. sodium dodecyl sulphate, dioctyl sodium sulphosuccinate, hexadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide and Triton X-100, has been examined by studying the effect of varying surfactant concentrations on enzyme activities as well as by determining the time-dependent inactivation and the time-independent inhibition. The kinetic parameters, Km and Vmax, for alpha-chymotrypsin-catalysed reaction in presence of sodium dodecyl sulphate were evaluated. Anionic surfactants markedly decreased enzyme activity, whereas cationic surfactants were less effective. Nonionics showed no effect. This change in enzyme activity was also dependent on the nature of enzyme.
...
PMID:Stability and kinetic behaviour of some enzymes in surfactant environment. 263 63

The primary structure of bovine milk lipoprotein lipase (bLPL) was determined by alignment of peptides produced by tryptic digestion, Staphylococcus aureus V8 protease digestion, and cyanogen bromide cleavage. bLPL consists of 450 amino acid residues. Most tryptic peptides were isolated and analyzed, except for the dipeptide, Glu-Lys (position 423-424), and the 2 Lys at positions 416 and 488. Peptides resulting from digestion by S. aureus V8 protease and cyanogen bromide cleavage filled the missing part and completed the primary sequence of bLPL. The NH2 terminus of bLPL was determined to be Asp by sequencing the intact protein with a gas phase sequencer for up to 30 residues, whereas the COOH terminus was identified as Gly through, carboxyl peptidase Y cleavage. The enzyme contains 10 cysteine residues, all of which exist in disulfide linkages. They are formed between Cys29 and Cys42, Cys218 and Cys241, Cys266 and Cys285, Cys277, and Cys280, and Cys420 and Cys440. The sites of N-glycosylation were identified at Asn44 and Asn361. In accordance with a common structural homology of serine-type esterases, -G-X-S-X-G- (Yang, C. Y., Manoogian, D., Pao, Q., Lee, F., Knapp, R. D., Gotto, A. M., Jr., and Pownall, H. J. (1987) J. Biol. Chem., 262, 3086-3191), the active site serine of bLPL was assigned to the serine at position 134. The chymotrypsin nick of bLPL was determined to be between residues 390 and 391. A model of the enzyme is proposed on the basis of our data and available chemical data.
...
PMID:Structure of bovine milk lipoprotein lipase. 267 42

Bacteriorhodopsin (bR) was regenerated from the cation-depleted blue membrane with pentaammineaquocobalt(III) tetrafluoroborate [( Co(NH3)5H2O]3+[BF4-]3). Illumination of the sample with orange light decreased the extinction at 568 nm concomitantly with a hypsochromic shift of the absorption maximum. The photocycle of this sample was inhibited, and the rate of proton pumping was reduced. Chymotryptic cleavage of the corresponding apomembrane into the two fragments C1 and C2 and their subsequent separation revealed that cobalt label is only attached to C1. The maximal incorporation of Co into this peptide was 0.3 Co/C1. After cleavage of C1 with cyanogen bromide and subsequent proteolysis with trypsin and chymotrypsin, this modification could be associated with peptides from cyanogen bromide fragments 6 and 9. The sequences were determined to be 101Val-Asp-Ala-Asp-Gln and 228Ala-Ile-Phe-Gly-Glu-Ala-Glu-Ala. These peptides contain the sequences Asp-Ala-Asp and Glu-Ala-Glu, respectively, which might be constituents of the same cation binding site. The observation that the incorporation of Co into bacteriorhodopsin is enhanced under illumination with orange light indicates that this site might be involved in the proton uptake.
...
PMID:Modification of two peptides of bacteriorhodopsin with a pentaamminecobalt (III) complex. 277 14

Superoxide anion (O2-) generated from xanthine oxidase/xanthine has been used to decrease the half life of endothelium derived relaxing factor (EDRF). However, by itself, xanthine oxidase causes endothelium dependent relaxation. This relaxation is unrelated to the oxidative property of the enzyme since it is not inhibited by allopurinol. In addition, the relaxation is not inhibited by the cyclooxygenase inhibitor, indomethacin, or the phospholipase A2 inhibitor, p-bromophenacyl bromide. On the other hand the relaxation is inhibited by the trypsin inhibitor (TI) from chicken egg white. A similar endothelium dependent relaxation elicited by pancreatin and trypsin is also inhibited by TI. Pancreatin used in the preparation of xanthine oxidase contains trypsin, chymotrypsin and carboxypeptidase. When compared to trypsin both chymotrypsin and carboxypeptidase elicit little relaxation. Thus the endothelium dependent relaxation elicited by xanthine oxidase is likely due to contamination with trypsin. Our results emphasize that when the superoxide generating system, xanthine oxidase/xanthine is used to study the effect of oxygen radicals on EDRF, it is advantageous to ensure that only purified preparations of xanthine oxidase are used.
...
PMID:Xanthine oxidase and endothelium dependent relaxation. 282 Apr 11

The occasional cleavage of the Pseudomonas cytochrome-c peroxidase (ferrocytochrome-c:hydrogen-peroxide oxidoreductase, EC 1.11.1.5) molecule into two well-defined fragments during the preparation of the enzyme is shown to be identical to that caused by elastase isolated from the culture solution of Pseudomonas aeruginosa. A cyanogen bromide fragmentation of proteolytically cleaved and of intact enzyme shows the cleaved peptide bond to be situated in cyanogen bromide fragment II. The amino-acid sequence of this fragment was established by sequencing peptides obtained with trypsin, thermolysin, chymotrypsin and o-iodosobenzoate. It is concluded from the sequence homology that the polypeptide chain of Pseudomonas peroxidase is wrapped around the high-potential heme in a similar manner as in high-potential cytochromes c in general. The specific proteolytic cleavage occurs at a Ser-Val (Leu-Pro) region which is assumed to be the site of attachment between enzyme and membrane. The cleavage of the Ser-Val bond renders the peroxidase molecule enzymatically inactive by impeding the conformational changes essential for the function of the native enzyme.
...
PMID:Specific cleavage of Pseudomonas cytochrome-c peroxidase by elastase from Pseudomonas aeruginosa. 282 23

The sequence of porcine pancreatic spasmolytic polypeptide has been established by a variety of techniques including manual as well as automatic sequencing of fragments resulting from the cleavage of reduced and S-carboxymethylated pancreatic spasmolytic polypeptide with trypsin, chymotrypsin, clostripain, cyanogen bromide and formic acid. The N- and C-terminal sequences were established using pyroglutamate amino-peptidase and carboxypeptidase A, respectively. Pancreatic spasmolytic polypeptide contains 106 amino acid residues in a single chain with seven S-S bridges and a pyroglutamyl blocked N-terminal. The alignment of the sequences representing amino acids 14-49 and 63-98 shows pair-wise identical amino acid residues in 18 out of 36 positions, indicating that these two "domains" have been derived from a common gene.
...
PMID:The amino acid sequence of pancreatic spasmolytic polypeptide. 285 75

A cyanogen bromide fragment derived from the K88ab adhesin inhibited the hemagglutinating activity of K88 fibrillae. Smaller fragments which inhibited the adherence of K88 fibrillae to erythrocytes or to intestinal epithelial cells were obtained by digestion of K88ab fibrillae with alpha-chymotrypsin. Active peptides were isolated from the digestion mixture and identified as Ser-Leu-Phe and Ala-Ile-Phe. Both tripeptides correspond to the peptide stretches Ser-148-Leu-Phe-150 and Ala-156-Ile-Phe-158, respectively, which are part of conserved regions in the primary structure of the K88 variants ab, ac, and ad. The isolated tripeptides inhibited the hemagglutinating activity of purified K88 fibrillae in the 1 to 5 microM range, while adherence of the fibrillae to intestinal epithelial cell brush borders was inhibited in the 10 to 50 microM range. Furthermore, the tripeptides were capable of eluting attached bacteria from agglutinated erythrocytes. The inhibitory activity of the isolated peptides was confirmed by testing various synthetic peptides for their ability to inhibit the interaction of the different K88 variants with various species of erythrocytes. The significance of these findings for the localization of the receptor-binding domain is discussed.
...
PMID:Inhibition of adhesive activity of K88 fibrillae by peptides derived from the K88 adhesin. 287 31

A proteinase inhibitor for elastases was isolated from extracts of the sea anemone Anemonia sulcata and purified to apparent homogeneity. The procedure comprises ethanolic extraction of the deep-frozen animals followed by gel filtration on Sephadex G-50 and by ion exchange chromatography on DEAE-Sephadex A-25 and SP-Sephadex C-25 and by hydroxylapatite chromatography. The slightly acidic inhibitor (isoelectric point 5.9) is a small protein consisting of 48 amino-acid residues without tryptophan and phenylalanine. The single chain molecule contains two methionines and no free sulfhydryl group but six cysteines presumably forming disulfide bonds. Reaction with cyanogen bromide abolishes the inhibitory properties. The inhibitor exhibits a rather narrow specificity for elastases. It strongly inhibits porcine pancreatic elastase in a permanent fashion with an equilibrium dissociation constant Ki of about 10(-10)M and somewhat weaker the elastase from human leucocytes with a Ki of about 10(-7)M. No obvious inhibition is observed of other serine proteinase such as bovine trypsin, bovine chymotrypsin, subtilisin from Bacillus subtilis and cathepsin G from human leucocytes when tested with synthetic substrates.
...
PMID:A new inhibitor of elastase from the sea anemone (Anemonia sulcata). 288 64

To clarify the characteristics of myosin isozymes in the atrium, we fractionated two isoforms of myosin heavy chain (HC), atrial HC alpha (A-HC alpha) and HC beta (A-HC beta), from the canine heart by affinity chromatography, using monoclonal antibodies specific for HC alpha (CMA19) and HC beta (HMC50), respectively, and then compared their peptide composition and enzymatic properties with those of ventricular HC alpha (V-HC alpha) and HC beta (V-HC beta). The reactivity of these isozymes with three monoclonal antibodies revealed that there are at least three different epitopes between A-HC alpha and A-HC beta. Differences in the primary structure of A-HC alpha and A-HC beta were confirmed by one- and two-dimensional gel electrophoretic analyses of these peptides, produced by digestion with alpha-chymotrypsin and cyanogen bromide (CNBr). A-HC alpha and V-HC alpha were indistinguishable proteins, and A-HC beta was also very similar to V-HC beta. Furthermore, there were differences between A-HC alpha and A-HC beta in their Ca2+-activated ATPase activities. The ATPase activity of A-HC beta was lower than that of A-HC alpha and was similar to that of V-HC beta. We concluded that there are two different isozymes of myosin heavy chain in the atrium (A-HC alpha and A-HC beta), as well as in the ventricle (V-HC alpha and V-HC beta), and that A-HC beta is very similar to V-HC beta, the predominant form of ventricular myosin, in its molecular structure and enzymatic activity.
...
PMID:Isolation and characterization of two isozymes of myosin heavy chain from canine atrium. 293 78

Microvilli isolated from the MAT-C1 ascites subline of the 13762 rat mammary adenocarcinoma contain a major calcium-sensitive microfilament-binding protein, AMV-p35 (ascites microvillar p35). Association of AMV-p35 with microfilament cores during Triton X-100 extraction of the microvilli is half-maximal at 0.1-0.2 mM calcium. The protein, which comprises 6% of the total microvillar protein, can be isolated from microfilament cores prepared in the presence of calcium by extraction with EGTA and purification by ion-exchange chromatography. Alternatively, the protein can be isolated from Triton extracts of microvilli prepared in the absence of calcium by precipitation with calcium, solubilization of the precipitate with EGTA, and chromatography on an ion-exchange column. AMV-p35 binds to phosphatidylserine liposomes and F-actin with half-maximal calcium concentrations of about 10 microM and 0.2 mM, respectively. Treatment of AMV-p35 with chymotrypsin yields a 33,000-dalton fragment, behavior similar to the tyrosine kinase substrates calpactins I and II and lipocortins I and II. Immunoblot analyses using antibodies directed against calpactin I, lipocortin I, and lipocortin II showed strong reactivity of AMV-p35 with anti-calpactin I and anti-lipocortin II, but little reactivity toward anti-lipocortin I. The close relationship between AMV-p35 and calpactin I was verified by amino acid sequence analyses of peptides isolated from cyanogen bromide digests of AMV-p35. By gel filtration and velocity sedimentation analyses purified AMV-p35 is a 35,000-dalton monomer. Moreover, AMV-p35 extracted directly from microvilli in Triton/EGTA also behaves as a 35,000-dalton menomer. These findings indicate that AMV-p35 is closely related to the pp60src kinase substrate calpactin I (p36). However, AMV-p35 occurs in the microvilli as a monomer rather than as the heterotetrameric calpactin found in several other cell types.
...
PMID:Isolation of a calcium-sensitive, 35,000-dalton microfilament- and liposome-binding protein from ascites tumor cell microvilli: identification as monomeric calpactin. 296 74


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

---