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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bovine pancreatic ribonuclease (RNase) A and S protein (enzymatically inactive proteolytic fragment of RNase A which contains RNA binding site) stimulate the activation, as evidenced by increasing DNA-cellulose binding, of highly purified rat hepatic glucocorticoid-receptor complexes. These effects are dose dependent with maximal stimulation of DNA-cellulose binding being detected at approximately 500 micrograms (50 units of RNase A/mL). RNase A and S protein do not enhance DNA-cellulose binding via their ability to interact directly with DNA or to increase nonspecific binding of receptors to cellulose. Neither S peptide (enzymatically inactive proteolytic fragment which lacks RNA binding site) nor cytochrome c, a nonspecific basic DNA binding protein, mimics these effects. RNase A and S protein do not stimulate the conformational change which is associated with activation and is reflected in a shift in the elution profile of receptor complexes from DEAE-cellulose. In contrast, these two proteins interact with previously heat-activated receptor complexes to further enhance their DNA-cellulose binding capacity and thus mimic the effects of an endogenous heat-stable cytoplasmic protein(s) which also function(s) during step 2 of in vitro activation [Schmidt, T. J., Miller-Diener, A., Webb, M. L., & Litwack, G. (1985) J. Biol. Chem. 260, 16255-16262]. Preadsorption of RNase A and S protein to an RNase affinity resin containing an inhibitory RNA analogue, or trypsin digestion of the RNA binding site within S protein, eliminates the subsequent ability of these two proteins to stimulate DNA-cellulose binding of the purified receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of bovine pancreatic ribonuclease A, S protein, and S peptide on activation of purified rat hepatic glucocorticoid-receptor complexes. 379 Apr 97

Splenic T lymphocytes of complete Freund's adjuvant (CFA)-treated guinea pigs spontaneously produce a lymphokine, eosinophil-directed chemotactic inhibitory factor (ECIF), which selectively inhibits the chemotactic response of the treated eosinophils to a certain chemotactic lymphokine for eosinophils. In the present paper, induction of spontaneous ECIF production was examined in CFA-treated guinea pigs. Although short-time (3-hr) cultured supernatants of CFA-treated spleen cells exhibited little or no ECIF activity, the supernatants could stimulate normal T lymphocytes to produce and release distinct ECIF activity. The factor with ECIF-releasing activity (ECIF-RF) was produced by splenic adherent cells of CFA-treated animals. ECIF-RF activity was absorbed only by T lymphocytes, suggesting that target cells of ECIF are T lymphocytes. ECIF-RF activity was eluted near cytochrome c (MW 12,500) on a Sephadex G-100 column. It was further found that ECIF-RF was sensitive to heating at 56 degrees C, to enzyme treatment with trypsin and neuraminidase, and to acid and alkaline condition. We thus concluded that ECIF-RF derived from adherent cells of CFA-treated animals may be involved in the suppression of cell-mediated tissue eosinophilia by stimulation of T lymphocytes to produce and release ECIF activity.
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PMID:The regulation of tissue eosinophilia. V. Induction of lymphocyte-derived eosinophil chemotactic inhibitory factor production by a macrophage product from complete Freund's adjuvant-treated guinea pigs. 380 11

Exon-intron structures of eukaryotic genes were examined closely in their relation to primary and tertiary structures of the proteins they encode. Specific attention was given to the introns of genes encoding proteins having no repeats in their amino acid sequences. such introns have been shown to be located at sites corresponding to inter-domain or inter-module junctions of proteins identified in their three dimensional structures. "Modules," compact structural units in globular domains of proteins, are identified by drawing a distance map. Intron positions are found to correspond to intermodule junctions in various proteins whose X-ray crystallographic data are available: the globin family, CEWL, ovomucoid, cytochrome c, ADH, and trypsin-like serine proteinases. The good correspondence between intron positions and intermodule junctions excludes a mechanism of random insertion of introns, because the probability of intron insertion at each intermodule junction is extraordinarily small. Intron positions have been very stable and well conserved during evolution. However, at some inter-module junctions no introns are found. Modules in small proteins having no core modules buried in their interior have a character suitable for recruitment through their assembly into a stable domain; one side of them is rich in hydrophobic residues and the other in hydrophilic residues. Functionally important residues are scattered on different modules in the proteins examined. Based on these observations, the role of modules in the precellular period was conjectured: some of them might be functionally active by themselves but most modules might be only segments who could function as an active protein only in an assembly. The origin of introns might be traced back prior to the divergence of prokaryotes and eukaryotes.
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PMID:Protein structures and split genes. 391 83

Cu-Zn superoxide dismutase was purified to homogeneity from mixed pig blood and from a single pig. The isolated product had an absorption ratio 280/260 nm of 0.91, a specific activity of 3 000 +/- 200 units (cytochrome c reduction test), and an isoelectric point of 7.5 (chromatofocusing) or 7.25 (isoelectric focusing), respectively. Sequence determination was performed by automated solid-phase Edman degradation of fragments of the reduced S-carboxymethylated proteins obtained by digestion with trypsin or Staphylococcus aureus proteinase V8 or treatment with cyanogen bromide. Acetylation of the N-terminus was confirmed by comparing high performance liquid chromatography retention times of N-terminal peptides with those of authentic samples. Sequencing of the superoxide dismutase of mixed porcine blood revealed heterogeneity (70% Leu; 30% Val at position 29), whereas the sample derived from a single French pig proved to be homogeneous (100% Leu at position 29). The complete sequence of pig superoxide dismutase comprised 152 amino-acid residues, which corresponds to a theoretical molecular mass of 15 800 Da per subunit, and exhibited the expected high homology with those of other mammals. The aspartate and all 7 histidine residues known to complex the metal ions in bovine superoxide dismutase are conserved in the porcine sequence at the homologous positions Asp82 and His45, His47, His62, His70, His79, His119, respectively.
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PMID:The primary structure of porcine Cu-Zn superoxide dismutase. Evidence for allotypes of superoxide dismutase in pigs. 402 96

A heme-octapeptide (mol wt 1,550) has been obtained from cytochrome c by successive pepsin and trypsin hydrolysis and purified by gel filtration and countercurrent distribution. It possesses peroxidatic activity characterized by an apparent K(m) of 0.2 M, an apparent v(max) of 4 mmol/min per mg of peptide, and a pH optimum of 7.0. Using a novel two-step conjugation procedure, the heme-octapeptide was coupled to rabbit Fab antibody fragments by first derivatizing it with the N-hydroxysuccinimide ester of p-formylbenzoic acid and subsequently allowing it to form a Schiff base with the amino groups of Fab. Stable covalent linkages were then obtained by reduction of the Schiff bases with sodium borohydride. The conjugate consists of approximately 2 heme-octapeptides attached to each Fab molecule. The molecular weight is 45,000 daltons when coupled to sheep Fab and 50,000 daltons with a Stokes radius of 32 A, when conjugated to rabbit Fab. Its peroxidatic activity is characterized by an apparent K(m) of 0.4 M, an apparent v(max) of 0.4 mmol/min and per mg of attached heme-octapeptide and a pH optimum of 7.0. The conjugate has been used for the localization at the electron microscope level of secretory immunoglobulins in the mammary gland of lactating rabbits.
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PMID:Preparation and characterization of an immuno-electron microscope tracer consisting of a heme-octapeptide coupled to fab. 435 86

Chromous ion reacts with ferricytochrome c to yield a one-to-one Cr(III)-ferrocytochrome c complex. This material, when hydrolyzed by trypsin and subjected to chromatographic procedures, yielded two fragments containing chromium. The amino-acid compositions and chemical characteristics of each of these fragments indicated that the chromium had crosslinked two segments of polypeptide chain; these were residues 40-53-Cr(III)-residues 61-72 and residues 40-53-Cr(III)-residues 61-73. Examination of a model of the ferricytochrome c molecule indicated that only two residues of the crosslinked peptides were sufficiently close to allow crosslinking to take place. These residues were tyrosine 67 and asparagine 52. Enzymatic hydrolysis of one of those fragments by aminopeptidase M supported this identification. The position of the chromic ion implies what is the path of electron transfer from the chromous ion to the ferric ion in this chemical reduction of cytochrome c, and suggests a possible path of electron transfer in biological oxidation-reduction reactions.
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PMID:Electron transfer reactions in biological systems: the reduction of ferricytochrome c by chromous ions. 436 36

1. Trypsin and ribonuclease were filtered through dextran gel (Sephadex G-100) columns in the absence and presence of their respective substrates. In the presence of their high-molecular-weight substrates the enzymes emerged earlier from the columns. This appeared to be due to the reversible formation of specific enzyme-substrate complexes. 2. The possibility of separation of an enzyme from other proteins with similar molecular weights was demonstrated with trypsin and cytochrome c in the presence of casein.
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PMID:Dextran-gel filtration of enzymes in the presence of their high-molecular-weight substrates. 593 53

A simple procedure is developed for estimation of the damage rate of inner membrane of heart mitochondria. In the assay the rate of succinate oxidation was measured using bromthymol blue as an inhibitor of succinate transport. Bromthymol blue at low concentration (12 microM) functioned as a mixed type inhibitor of succinate oxidation, whereas at high concentrations--as uncompetitive inhibitor. Polarographic registration of cytochrome c content and of the rate of ascorbate oxidation in the samples containing Triton X-100 and free of the detergent was more sensitive procedure as compared with spectrophotometric measurement of reduced cytochrome c oxidation in estimation of the damage rate of outer mitochondrial membranes. The damage rates of outer and inner membranes of heart mitochondria isolated by a procedure which included the treatment with trypsin were equal to 8.43 +/- 0.74% and 8.04 +/- 1.9%, respectively, while in those isolated without the trypsin treatment--12.8 +/- 1.5% and 13.3 +/- 1.8%, respectively.
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PMID:[Estimation of intact outer and inner membranes of heart mitochondria]. 609 28

In attempts to produce fragments of an allergenic molecule which would retain allergenic and/or antigenic determinant(s), the cytochrome c of ryegrass (RG) pollen, which had been shown to be an allergenic constituent of this pollen, was digested with trypsin and chymotrypsin and the resulting fragments were separated by high performance liquid chromatography. Several of these fragments were shown, with the aid of the radioallergosorbent test and solid phase radioimmunoassays, to bind IgE antibodies present in a pool of six sera from grass-sensitive patients and three murine monoclonal antibodies, designated as Mab 41, Mab 42 and Mab 43, which had been originally produced against the crossreacting cytochrome c of Kentucky bluegrass (KBG). In summary, (i) fragments C-67 and C-74 reacted with all antibodies, (ii) fragments T-45, T-46 and C-69 bound to human IgE antibodies as well as to Mab 41 and Mab 42, but not to Mab 43, (iii) fragment T-44 reacted only with Mab 41 and Mab 42, and (iv) fragment C-83 bound only Mab 42 and Mab 43. On the basis of these results, it is concluded that (i) immunochemically active fragments of the RG cytochrome c can be readily produced by enzymatic degradation, (ii) there is significant crossreaction between the antigenic determinants of RG and KBG cytochromes c, (iii) whereas all fragments possessed at least two of the original antigenic determinants, fragments C-83 and T-44 were devoid of allergenic determinants, (iv) the antigenic determinants recognized by Mab 41 and Mab 42 were different from those reacting with human IgE antibodies and Mab 43, (v) each of the three monoclonal antibodies recognized a distinct antigenic determinant, (vi) fragments C-67 and C-74 possessed all determinants recognized by the human IgE and mouse antibodies used.
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PMID:Determinants of ryegrass pollen cytochrome c recognized by human IgE and murine monoclonal antibodies. 620 97

Incubation of the 125I-labeled apoprotein, prepared from 125I-labeled iso-1-cytochrome c, with a yeast mitochondrial fraction in the presence of hemin, NADPH, and an extract of the postmitochondrial fraction at 32 +/- 1 degree C for 30 min has resulted in formation of cytochrome c-like species in yields of up to 35%. This radioactive synthesized species contains a functional group which responds to reduction with ascorbate and oxidation with K3Fe(CN)6 in that it is resistant in the reduced form and susceptible in the oxidized form to trypsin action in a manner characteristic of native cytochrome c. The functional group cannot be removed from the protein by cold HCl-acetone or 8 M urea treatment. The reduced form of the synthesized species exhibits resistance against autoxidation and the oxidized form can be reduced also by cytochrome b2. The synthesized species exhibits the same compact hydrodynamic volume of native cytochrome c. Treatment with silver sulfate followed by incubation with dithiothreitol converts the synthesized species to the original apoprotein as judged by an increase in the hydrodynamic volume. Thus, the synthesized species is indistinguishable from the original labeled iso-1-cytochrome c by these measurements; i.e. the synthesized species consists of the apoprotein to which heme is covalently attached through the thioether bond(s). The active factor of the mitochondrial fraction is heat-labile. The synthetic activity is strongly dependent on pH with a maximum approximately at pH 7.0. Hemin (or heme) appears to be required for this synthesis. The postmitochondrial fraction is inactive by itself. However, its addition markedly increases the synthetic activity. This factor is heat-stable, soluble in 80% methanol (or 75% ethanol), and insoluble in ethyl ether or ethyl acetate. Addition of NADP(H) (or NAD(H)) also increases the synthetic activity, the reduced form being more effective than the oxidized form. The postmitochondrial factor and the pyridine nucleotides appear to enhance the effect of each other. Thus, it seems that cytochrome c or a cytochrome c-like species is formed from the apoprotein and heme (or hemin) by an enzyme, cytochrome c synthetase, present in mitochondria.
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PMID:Formation of an iso-1-cytochrome c-like species containing a covalently bonded heme group from the apoprotein by a yeast cell-free system in the presence of hemin. 624 50


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