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)

It has previously been shown that mammalian RNA-peptidyl complexes are found in close association with tRNA, but can be separated from the bulk of the tRNA by benzoylated diethylaminoethylcellulose chromatography (Kull, F.J., and Soodak, M. (1971), Biochim. Biophys. Acta 246, l; Gadski, R.A., and Kull, F.J. (1973), Biochemistry 12, 1907). These studies also showed that under aminoacylation conditions the complex fractions were able to act as acceptors for certain amino acids and that the formation of porcine thyroid tyrosyl-complex II was particularly high. Because of this high acceptor function, and because of the importance of tyrosine to thyroid metabolism, further studies were conducted comparing some of the properties of porcine thyroid tyrosyl-complex II with those of porcine thyroid tyrosyl-tRNA. Porcine thyroid tyrosyl-tRNA synthetase was purified in excess of 200-fold and characterized. It was found that maximal aminoacylation was achieved at pH 8.1 in the presence of 150 mM KCl. The Km for tyrosine was determined to be 3.0 X 10(-6) M. The purified thyroid tyrosyl-tRNA synthetase was used under aminoacylation conditions to prepare radioactively labeled porcine thyroid tyrosyl-tRNA and tyrosyl-complex II. Comparisons made using reversed-phase column chromatography (RPC-5) showed distinct differences between the two aminoacylated species and revealed, in addition, a number of isoaccepting forms of tyrosine tRNA. Tyrosyl-complex II was also found to differ from tyrosyl-tRNA in that it is more stable to deacylation at pH 7.0 and at pH 4.4 and to degradation by ribonuclease A. In addition, tyrosyl-complex II, unlike tyrosyl-tRNA, is degraded by trypsin. Ribosomal binding studies showed that tyrosyl-complex II did not respond to the codons for tyrosine, UpApU and UpApC, whereas tyrosyl-tRNA responded to both. It is suggested that thyroid tyrosine complex II is representative of a group of related complexes that constitute the complex II fraction and that, although the complexes resemble tRNA in many respects, they have distinctly different characteristics than conventional tRNA.
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PMID:Thyroid Ribonucleic Acid-Iodopeptides. Comparison of Tyrosyl-Complex II and Tyrosyl-tRNA. 0 30

The digestion of ribonuclease A by proteinase K yielded one major degradation product only, which could not be distinguished from ribonuclease S by electrophoretical and immunological methods. This component (ribonuclease K) possessing full catalytic activity was characterized to be (1--20/21--124) ribonuclease A. Combined action of proteinase K and trypsin on ribonuclease A leads to a significant increase of the inactivation rate which may be useful in the isolation of mRNA from polysomes.
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PMID:Ribonuclease A digestion by proteinase K. 15 63

Normal rat bone marrow cells incubated with serum or lymph from Nippostrongylus brasiliensis (Nb)-infected rats showed an increase in the proportion of IgE-bearing cells in culture. This effect was produced in a similar fashion by cell-free supernatants (CFS) from cultures of mesenteric lymph node cells obtained from Nb-infected rats. The action of CFS on bone marrow cells appeared to be specific for the generation of IgE-bearing cells since the proportion of IgM-bearing cells in the culture did not change. The IgE-bearing cells in bone marrow cell cultures consisted of small lymphocytes, blast cells, and mast cells, and the addition of CFS to the cultures predominantly increased the number of IgE-bearing blast cells. CFS was also effective in increasing the proportion of IgE-bearing small lymphocytes in cultures of normal mesenteric lymph node cells. Removal of IgE in CFS by an anti-IgE immunosorbent did not affect the ability of CFS to generate IgE-bearing cells. The factor(s) in CFS responsible for this activity was shown to migrate with serum beta-globulins in zone electrophoresis and to possess a molecular size of between 10(4) and 2 X 10(4) m.w. The ability of CFS to generate IgE-bearing cells was diminished by treatment with the enzymes trypsin and ribonuclease A, but was unaffected by chymotrypsin.
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PMID:IgE formation in the rat following infection with Nippostrongylus brasiliensis. III. Soluble factor for the generation of IgE-bearing lymphocytes. 30 98

1. The reactivities of phenylglyoxal (PGO), glyoxal (GO), and/or methylglyoxal (MGO) with several proteins, including ribonuclease A [EC 3.1.4.22] and its derivatives, alpha-chymotrypsin [EC 3.4.21.1], trypsin [EC 3.4.21.4], lysozyme [EC 3.2.1.17], pepsin [EC 3.4.23.1], rennin [EC 3.4.23.4], thermolysin, and insulin and its B chain, have been examined. From analyses of the reaction products, PGO was shown to be the most specific for arginine residues. GO and MGO also reacted rapidly with arginine residues, but they also reacted with lysine residues to a significant extent. A side reaction with N-terminal alpha-amino groups was observed with each of these reagents. 2. Two arginine residues out of four in ribonuclease A, two out of three in alpha-chymotrypsin, one out of two in trypsin, one out of two in pepsin, and one out of five in rennin appeared to react with PGO fairly rapidly, indicating a difference in the relative accessibility of these residues by the reagent. Extensive modification of the arginine residues by PGO occurred with RCM-derivatives of ribonuclease A and insulin B chain. The N-terminal isoleucine residues of alpha-chymotrypsin and trypsin appeared to be unreactive with PGO because of salt bridge formation with an aspartyl residue. The activity of alpha-chymotrypsin toward N-benzoyl-L-tyrosine ethyl ester and the lytic activity of lysozyme were lost rapidly on treatment with PGO, as in the case of ribonuclease A. Pepsin and rennin were only partially inactivated by reaction with PGO.
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PMID:Further studies on the reactions of phenylglyoxal and related reagents with proteins. 32 41

The dimethyl ester of bovine pancreatic ribonuclease-A (dimethyl RNAase-A), the initial product of esterification of RNAase-A in anhydrous methanolic HCl, was isolated in a homogeneous form. The two carboxy functions esterified in this derivative are those of glutamic acid-49 and aspartic acid-53. There were no changes in the u.v.-absorption spectral characteristics, the accessibility of the methionine residues, the resistance of the protein to proteolysis by trypsin and the antigenic behaviour of RNAase-A as a result of the esterification of these two carboxy groups. Dimethyl RNAase-A exhibited only 65% of the specific activity of RNAase-A, but still had the same K(m) value for both RNA and 2':3'-cyclic CMP. However, the V(max.) was decreased by about 35%. On careful hydrolysis of the methyl ester groups at pH9.5, dimethyl RNAase-A was converted back into RNAase-A. Limited proteolysis of dimethyl RNAase-A by subtilisin resulted in the formation of an active RNAase-S-type derivative, namely dimethyl RNAase-S, which was chromatographically distinct from dimethyl RNAase-A and had very nearly the same enzymic activity as dimethyl RNAase-A. Fractionation of dimethyl RNAase-S by trichloroacetic acid yielded dimethyl RNAase-S-protein and dimethyl RNAase-S-peptide, both of which were inactive by themselves but regenerated dimethyl RNAase-S when mixed together. Dimethyl RNAase-A-peptide was identical with RNAase-S-peptide. RNAase-S-protein could be generated from dimethyl RNAase-S-protein by careful hydrolysis of the methyl ester groups at pH9.5. The interaction of dimethyl RNAase-S-protein with RNAase-S-peptide appears to be about 4-fold weaker than that between the RNAase-S-protein and RNAase-S-peptide. Conceivably, the binding of the S-peptide ;tail' of dimethyl RNAase-A with the remainder of the molecule is similarly weaker than that in RNAase-A, and this brings about subtle changes in the geometrical orientation of the active-site amino acid residues of these modified methyl ester derivatives. It is suggested that these changes could be responsible for the generation of the catalytically less-efficient RNAase-A and RNAase-S molecules (dimethyl RNAase-A and dimethyl RNAase-S respectively).
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PMID:Structure and enzymic activity of ribonuclease-A esterified at glutamic acid-49 and aspartic acid-53. 70 73

A substance inhibitory to protein synthesis was purified from mouse skeletal muscle by gel filtration and ion-exchange chromatography, as well as by centrifugation on sucrose gradients. The molecular weight of the inhibitor, determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, was 71000. The inhibitory activity was insensitive to ribonuclease A, deoxyribonuclease I and phospholipase C. It was sensitive to Pronase treatment but insensitive to heat-treatment and trypsin degradation. The present results, taken together with previous studies, indicate that the site of action of the inhibitor is not on the initiation phase of protein synthesis but rather at a step after the binding of aminoacyl-tRNA to ribosomes. The increased inhibitor activity found in dystrophic muscle is discussed.
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PMID:Studies of a factor from dystrophic mouse muscle inhibitory towards protein synthesis. 74 60

Kinetic properties of protein methylase II (S-adenosymethionine:protein O-methyltransferase, EC 2.1.1.24) which methylates (esterifies) the free carboxyl side chains of amino acids in proteins was studied using various polypeptides as methyl acceptor substrates. Bovine pancreatic ribonuclease, a model substrate for the enzyme, was subjected to specific cleavage by cyanogen bromide, trypsin, and performic acid oxidation. Several polypeptide fragments derived were then separated by molecular sieve chromatography on a column of Sephadex G-25. The method was found to be very simple and gave good yields. Km values for these polypeptides as well as a few other protein substrates were determined. While Km values for the isolated peptides range generally between 4.8 and 0.7 X 10-3 M, those of native bovine panreatic ribonuclease, luteinizing hormone, and follicle-stimulating hormone were determined to be 4.0 X 10-4, 5.0 X 10-5, and 0.77 X 10-5, respectively. Sites of enzymatic methylation of the native ribonuclease were also investigated. Although polypeptides derived from the C-terminal and N-terminal regions of the molecule were found to accept methyl groups, they were unable to under go enzymatic methylation when native molecule was used as the substrate indicating that within the native ribonuclease these regions are in a conformation which do not allow them to be methylated by protein methylase II under the present assay conditions.
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PMID:A comparison of kinetic parameters of polypeptide substrates for protein methylase II. 78 14

Trypsin, pepsin and subtilisin have been used as conformational probes for the structure of bovine seminal ribonuclease BS-1 by studying, under definite conditions, their effects on the seminal enzyme, a dimeric protein made up to two identical subunits; on bovine pancreatic monomeric ribonuclease A (EC 3.1.4.22) with a polypeptide chain homologous to that of the seminal ribonuclease subunit chain; and on a monomeric, active and stable derivative of seminal ribonuclease. The results show: (1) that the C-terminal regions of the pancreatic and the seminal proteins are very similar as they appear to fit in an identical way to the active site of pepsin; (2) that the resistance of the N-terminal region of ribonuclease BS-1 to subtilisin is not due to the dimeric structure of the protein, but to the conformation of this region, where an essential feature is the presence of a proline residue at position 19; (3) that the monomer of ribonuclease BS-1 is resistant to tryptic action only when bound to the partner monomer in the quaternary structure of the protein. This indicates that dissociation of the seminal ribonuclease makes some potentially susceptible susceptible bond or bonds available to trypsin either through a conformational change of the protein subunit, or by simply exposing the protein area hidden at the intersubunit interfaces.
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PMID:Proteolytic enzymes as structural probes for ribonuclease BS-1. 78 46

The release of beta-lysin, which followed the intravenous injection of antigen-antibody complexes, did not take place when these complexes were added to citrated whole blood but did occur in heparinized blood. beta-Lysin release in heparinized blood was inhibited by citrate but were reversed by the addition of calcium ions that implicated complement reactions. Fourteen different enzymes were added to platelet-rich plasma (PRP). Streptokinase, neuraminidase, papain, phospholipase C, sulfatase, and trypsin caused platelets to release significant quantities of beta-lysin, whereas elastase, phosphatase, protease, ribonuclease A, hyaluronidase, lipase, and pepsin caused little or no increase in the plasma beta-lysin concentration. One enzyme, fibrinolysin, inactivated beta-lysin faster than it was released. The enzyme-induced release of beta-lysin from PRP was often accompanied by a reduction in the number of platelets. The intravenous injection of streptokinase, neuraminidase, and sulfatase caused in vivo releases of beta-lysin into the plasma. The platelet-aggregating substances collagen, arachidonic acid, and adenosine 5'-diphosphate caused beta-lysin to be released from PRP. The platelet-aggregating substances L-epinephrine, zymosan, fibrinogen, reserpine, and serotonin caused little or no release of beta-lysin from platelets. The results of this study indicate that the release of beta-lysin during antigen-antibody-complement reactions, blood coagulation, phagocytosis, and inflammation could be enzyme mediated.
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PMID:Release of beta-lysin from platelets caused by antigen-antibody complexes, purified enzymes, and platelet-aggregating substances. 84 4

The enthalpies of interaction of urea with five globular proteins, ribonuclease A, trypsin, beta-lacto-globulin, ovalbumin and bovine serum albumin have been measured in aqueous solution at pH 7.0, I=0.005 M and 25 degrees C over a range of urea molality m from 0-15 mmol g-1 (where a 1 molal solution contains 1 mmol g-1). For all the proteins the interaction is exothermic, and there is an appreciable heat evolution at low urea concentrations, m less than 5 mmol g-1, which increases sharply at higher urea concentrations when the proteins undergo unfolding. If account is taken of the endothermic enthalpies of unfolding of the native proteins, the enthalpies of interactions of urea per unit mass denatured protein lie in the range -45 to -75 J g-1, corresponding to an average binding enthalpy of -23 kJ mol-1 bound urea.
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PMID:The enthalpy of interaction of urea with some globular proteins. 95 43


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