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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteolytic digestion of the human T lymphoblastoid cell line (Molt-4) and of peripheral blood lymphocytes by trypsin, chymotrypsin, and pronase results in a progressive, time-and dose-dependent diminution of T lymphocyte-sheep red bloock cell (SRBC) rosette formation, whereas thrombin, plasmin, collagenase, DNAse, and phospholipase have not effect. Complete abrogation of SRBC binding is achieved when lymphocytes (1 x 108/ml) are incubated with either trypsin or chymotrypsin at 10 mug/ml for 30 min, and greater than 50% abrogation is observed between 3 to 10 min. Preincubation of SRBC with the 10 min and 20 min lymphocyte digest supernatants inhibited their subsequent binding by normal T lymphocytes by as much as 64%. Thirty-minute digests were less inhibitory. Equivalent digests from several human B lumphoblastoid cell lines and from a non-rosetting clone of Molt-4 cells were not inhibitory. Polyacrylamide gel electrophoresis followed by elution of serial gel slices revealed four distinct inhibitory bands (I-IV) in the 20-min digest supernatant whereas only bands I-III and band IV were present in the 10-min and 30-min digest supernatants, respectively, suggesting progressive proteolysis of a distinct receptor. These experiments indicate that the binding of SRBC by human T lymphocytes represents a receptor-ligand interaction rather than a nonspecific electrical charge phe nomenon and that the receptor is a discrete molecular species which can be isolated from the surface of T but not B lymphocytes by limited enzymatic proteolysis.
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PMID:Recovery of soluble sheep erythrocyte receptor from the T lymphocyte surface by proteolytic cleavage. 30 Mar 98

Our previous studies have shown that the two coronarodilatatory hypothalamic proteins isolated by us are not only carriers for neurohormones "K" and "C" but also procursors of coronarodilatory substances. In the present study we have looked at some physico-chemical properties of these proteins through isoelectric focusing and gel electrophoresis as well as the possibility of obtaining coronaroactive fragments by proteolytic enzymes. The results obtained have shown that the isoelectric points of the coronaroactive proteins are between pH 6.2 and 6.4. Polyacrylamide gel-electrophoresis has shown that one of the coronaroactive proteins, the carrier of neurohormone "C", moves towards the anode and is homogenous while carrier of neurohormone "K" is made up of two protein fractions. Under the action of certain enzymes (trypsin and pepsin) two coronaroactive fragments are obtained from the "neutral" protein carrier. Such an effect is not observed following the action of pronase and chymotrypsin. The physico-chemical properties of these fragments require further studies.
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PMID:[New findings concerning the coronaroactive proteins of the hypothalamus]. 80 92

The egg jelly-induced acrosome reaction of the sea urchin, Strongylocentrotus intermedius, was inhibited by succinyl-Leu-Leu-Val-Tyr-4-methyl-coumaryl-7-amide (Suc-Leu-Leu-Val-Tyr-MCA), but not by Suc-Ala-Ala-Pro-Phe-MCA. The proteases with hydrolytic activity toward the former were purified from sperm extract by DEAE-Sephacel and hydroxylapatite chromatographies, Sephacryl S-300 gel filtration, and heparin-Sepharose CL-6B chromatography. Two types of protease were separated, and the molecular weights were estimated to be 65 and 700 kDa, respectively, by gel filtration. The former was accompanied by hydrolytic activity toward Suc-Ala-Ala-Pro-Phe-MCA, which was not hydrolyzed by the latter. Polyacrylamide gel electrophoresis of 700 kDa protease gave a single protein band under nondenaturing conditions and at least eight bands in the range of 22-33 kDa in the presence of sodium dodecyl sulfate (SDS). The substrate specificity and the inhibitor sensitivity of 700 kDa protease indicate that it contains two types of the activity, one is chymotrypsin-type and the other trypsin-type. The former activity was enhanced by poly-L-lysine or SDS. These properties of 700 kDa protease are similar to those of proteasomes (multicatalytic proteinases) isolated from various eukaryotic sources. We had previously shown that inhibitors of chymotrypsin-like proteases inhibit the increase of intracellular Ca2+ concentration by egg jelly, resulting in the inhibition of the acrosome reaction of St. intermedius (Matsumura and Aketa, Gamete Res 23:255-266, 1989). Bringing these findings together, we suggest that the chymotrypsin-like activity of sperm proteasome participates in the onset of the acrosome reaction of St. intermedius.
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PMID:Proteasome (multicatalytic proteinase) of sea urchin sperm and its possible participation in the acrosome reaction. 187 26

Thyroid hormones are known to modulate the concentrations of epidermal growth factor (EGF) in the mouse submandibular gland (SMG); this action is presumably mediated by the nuclear triiodothyronine receptor. To test the hypothesis that thyroid hormones act to increase SMG EGF concentrations by increasing the number of poly(A)+ -specific mRNA, poly(A)+ RNA was isolated from SMGs of neonatal mice which had been treated daily from birth through to 21 days of age with thyroxine (T4,0.4 microgram/g body weight). Poly(A)+ RNA also was extracted from SMGs of intact 21-day-old mice which had received vehicle alone. No significant differences in total nucleic acid, total RNA, or poly(A)+ RNA yields were noted between the two groups of animals. The isolated poly(A)+ RNAs from T4-treated and control mice were translated in an in vitro wheat germ system. Although no significant differences in efficiency of [35S]cysteine incorporation into trichloracetic acid precipitable material were noted between the two poly(A)+ RNA preparations, a significantly greater proportion of radioactivity was immunoprecipitable by anti-EGF antiserum in the translation medium derived from T4-treated mice (17.2 +/- 0.9%, mean +/- SEM) than in that of control mice (7.3 +/- 0.5%, P less than 0.001). Polyacrylamide gel electrophoresis of the immunoprecipitates (IMMP) revealed the presence of three radioactive bands with apparent relative masses (MrS) of 12,000, 9000, and 6000. The latter species comigrated with purified EGF, [125I]EGF, and an IMMP of a SMG extract. The translation product IMMPs following polyacrylamide gel electrophoresis were iodinated and digested with alpha-chymotrypsin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thyroxine increases neonatal mouse submandibular gland mRNA-directed synthesis of epidermal growth factor. 242 79

In this paper two different aspects of androgen action are reviewed. Polyacrylamide gel electrophoresis of androgen receptors, photoaffinity labeled with R1881 showed that receptors isolated from both human prostate cells and calf uterine cytosol cells are proteins with a molecular mass of approx 110 kD. Purification to homogeneity of this form of the receptor from calf uterus also yielded a 110 kD protein. A molecular model for the DNA-binding form of the receptor is presented in which one polypeptide comprises three active domains: one for ligand binding, one for interaction with nuclear acceptor sites, and a third domain which modulates nuclear interaction. Mild digestion with chymotrypsin or a protease from rat prostates removes the modulating domain and leaves the ligand binding and nuclear interaction domain intact. Trypsin treatment yields a fragment of lower molecular mass containing the ligand binding domain with some affinity for RNA, but not DNA. In vitro studies with a human prostate tumor cell line (LNCaP), suggest that androgens not only directly effect cell growth, but also act indirectly. Both epidermal growth factor (EGF) and androgens stimulate cell growth. In addition androgens stimulate synthesis of receptors for EGF. Thus androgens effect tumor cell growth by autocrine or paracrine mechanisms by making the cells more sensitive for growth factor mediated stimuli.
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PMID:Mechanism of androgen action: recent observations on the domain structure of androgen receptors and the induction of EGF-receptors by androgens in prostate tumor cells. 264 38

31P Nuclear Magnetic Resonance (NMR) studies were performed on mono- and diisopropylphosphoryl derivatives of alpha-chymotrypsin, trypsin, and subtilisin. Questions addressed included the pKa of the active center Asp...His...Ser triad in both species. While the pKa in the diisopropylphosphoryl derivatives is near 7.4 (found in this and other laboratories earlier) and reflects a nearly normal imidazolium titration curve, the apparent pKa in the monoisopropylphosphoryl enzymes (obtained by "aging" of the diisopropylphosphoryl derivatives and monitored by 31P NMR) is between 9.7 and 11.4 depending on the protease. This latter "titration" of the 31P NMR signal is reversible and presumably reflects the interaction of the imidazolium positive charge with the monoanionic phosphodiester. Of the two tetrahedral intermediates, the properties of the monoisopropylphosphoryl enzyme are probably more representative of the tetrahedral oxyanionic intermediate invoked during peptide hydrolysis. The same NMR technique was used to determine the action of PAM (pyridine-2-aldoxime methiodide, a known "antidote" for acetylcholinesterase inactivated by diisopropylfluorophosphate), on the inactivated enzymes. It was clear that the "antidote" could reverse the diisopropylphosphorylation but was ineffective on the monoisopropylphosphoryl ("aged") enzyme. 11B NMR studies were performed on phenylboronic (PBA) acid and 3,5-bis-trifluoromethylphenylboronic acid in the absence and presence of chymotrypsin and subtilisin. At 22 degrees C the former, but not the latter, compound was in fast exchange between the free and enzyme bound states. The relaxation parameters could be calculated for the bound PBA in chymotrypsin and the fluorinated analogue in subtilisin and clearly indicated that the boron nucleus was tetrahedral in the active centers, a good analogue for the tetrahedral oxyanionic intermediate.
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PMID:Multinuclear magnetic resonance studies on serine protease transition state analogues. 276 49

The palmitoylation site of the membrane glycoprotein E1 of Semliki Forest virus (SFV) has been identified by chemical analysis of an acylpeptide. 3H-Palmitoylated E1 isolated from SFV grown in baby hamster kidney cells was digested with chymotrypsin and the resulting peptides subjected to high performance liquid chromatography on a wide-pore column. The 3H-acylated peptide fraction peaked at above 60% 2-propanol in the eluent, indicating its hydrophobic character. Polyacrylamide gel electrophoresis analysis revealed a molecular weight of about Mr = 6000 for the radiolabeled peptide. Manual sequencing of this material by the 4-N,N'-dimethylaminoazobenzene-4'-isothiocyanate/phenylisothiocyanate procedure on solid phase revealed the amino-terminal sequence Ala-Ala-Ser-His-Ser-Asn-Val-Val-Phe-Pro. The same peptide also labels with [35S]cysteine. Comparison with the deduced amino acid sequence of E1 revealed that the palmitoylated peptide contains at least 43 amino acid residues, and thus includes the membrane spanning region down to the only cysteine residue five positions up from the carboxyl terminus of E1. Since [3H]palmitic acid was cleaved from E1 with thiol reagents, and since the peptide labels with [14C]iodoacetamide only after the release of fatty acids by hydroxylamine treatment, cysteine in position 433 represents the palmitoylation site in SFV E1.
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PMID:Chemical identification of cysteine as palmitoylation site in a transmembrane protein (Semliki Forest virus E1). 314 15

The changes in the quaternary structure of chicken skeletal muscle phosphorylase kinase during limited proteolysis by trypsin and chymotrypsin were studied. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of the products of phosphorylase kinase limited proteolysis revealed a similarity in the structure of the alpha'- and beta-subunits and some differences in the structure of the gamma-subunits of the chicken and rabbit enzymes. Phosphorylation with the catalytic subunit of cAMP-dependent protein kinase (up to 2 mol of 32P/mol of alpha' beta gamma' sigma monomer) and autophosphorylation (up to 8 mol of 32P/mol alpha' beta gamma' delta monomer) increased the activity of chicken phosphorylase kinase 1.5-fold and 2.0-fold, respectively. The incorporation of phosphate into the alpha' and beta-subunits in the course of the protein kinase-catalyzed reaction was demonstrated.
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PMID:[Limited proteolysis and phosphorylation of phosphorylase kinase from chicken skeletal muscles]. 331 11

Partially purified IgE receptor(s) of rat basophilic leukemia cells (RBL) designated R and H and having apparent molecular weight of 45,000 and 55,000 daltons, respectively, were subjected to proteolysis with papain. Polyacrylamide gel electrophoresis of the digests in the presence of sodium dodecyl sulfate revealed a difference in the size and number of the fragments produced. These results suggest that these two receptor molecules are different with respect to amino acid composition and sequence. Whole Nonidet P-40 extracts of RBL cells were also subjected to digestions with papain, trypsin and chymotrypsin in an attempt to obtain receptor fragments still capable of binding to IgE-Sepharose. Treatment with papain produced a 38,000 dalton fragment of H but no fragments of R which retained the ability to bind to IgE. Tryptic and chymotryptic treatment produced a 41,000 dalton fragment of H with affinity for IgE. The IgE-binding site of R was either destroyed or not affected at all.
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PMID:Proteolytic fragments of the receptors for IgE. 621 Jun 30

The lymphokine activity, macrophage aggregation factor (MAgF) has been investigated further. Activity was consistently found in 24 hr test, but not control, spleen cell culture supernatants. This was higher after dialysis against water, than in the original culture supernatants. MAgF was heat-stable, inactivated by alpha-chymotrypsin, partially inactivated by trypsin and not affected by neuraminidase. Activity was recovered from the supernatant after protein precipitation with 1 M perchloric acid, leading to a modest purification. Activity was only marginally reduced after treatment with periodate, and was not absorbed by Concanavalin A-Sepharose. Polyacrylamide gel electrophoresis showed that MAgF migrated cathodally to albumin. Aggregation, as measured in a batch centrifugation assay, was an expression both of cell-substrate and cell--cell adhesion.
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PMID:Macrophage aggregation factor: some properties. 628 38


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