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)

Human intrinsic factor was digested by trypsin and the resulting peptides purified by gelfiltration. Two peptides were sequenced to a total of 61 amino acid residues. Including the sequence for the N-terminal peptide and four cyanogen bromide peptides previously reported, we have now determined a total of 163 amino acid residues, that is a fraction of about 0.40 of the primary structure of human intrinsic factor. The 110 of the 163 residues known of human intrinsic factor are identical to the sequence of rat intrinsic factor.
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PMID:Human intrinsic factor. Its primary structure compared to the primary structure of rat intrinsic factor. 277 49

The viral capsid protein VP1 of human rhinovirus serotype 2 (HRV2) was cleaved with cyanogen bromide. The peptides thus obtained were separated on an HPLC butyl reversed phase column. Their positions on VP1 were determined by amino-terminal sequencing using the known nucleotide sequence of the genomic RNA of HRV2. The putative carboxy-terminal peptide was further cleaved with trypsin and the resulting fragments were separated on a C18 reversed phase column. Amino-terminus of sequencing of the C-terminal peptide revealed alanine as being the carboxy terminus of VP1 in HRV2. This indicates that the processing of the polyprotein is different in HRV2 from the processing previously reported for HRV14 and poliovirus.
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PMID:Cleavage site between VP1 and P2A of human rhinovirus is different in serotypes 2 and 14. 282 58

Lipotropin and peptides related to beta-endorphin were extracted from the anterior pituitary and the pars intermedia of porcine pituitary and were resolved by gel exclusion and ion exchange chromatography. Possible heterogeneity in the structure of the lipotropin was investigated by identifying the C-terminal fragment released by limited proteolysis with trypsin; the cleavage was restricted to the carboxyl group of arginine residues by employing citraconylation to protect the epsilon-NH2 groups of lysine. The lipotropin obtained from both regions of the pituitary gave rise to the same C-terminal peptide which contained the 31-residue sequence of beta-endorphin; none of the 26- and 27-residue forms was detected. In contrast, the beta-endorphin-related peptides that were isolated directly from the pars intermedia exhibited a high degree of C-terminal proteolysis: they were present principally as the 26- and 27-residue peptides. The results demonstrate that lipotropin differs from beta-endorphin in that it occurs exclusively in the form that contains the full C-terminal sequence. It is concluded that during biosynthesis lipotropin undergoes conversion to beta-endorphin before proteolysis takes place at the C-terminus. The processing reactions that convert lipotropin to beta-endorphin 1-31 and beta-endorphin 1-31 to beta-endorphin 1-27 are thus ordered and not competitive. The results also indicate that glycylglutamine, the bioactive C-terminal dipeptide of lipotropin, is formed from beta-endorphin and not from lipotropin.
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PMID:Sequential formation of beta-endorphin-related peptides in porcine pituitary. 296 43

The primary structure of Cu-Zn superoxide dismutase from rabbit liver was investigated. The reduced and S-carboxymethylated enzyme was treated with cyanogen bromide, trypsin or Staphylococcus aureus proteinase V8. The resulting peptides were separated by high-performance liquid chromatography and sequenced by automated Edman degradation. With the exception of the N- and C-terminus the complete sequence was established by means of overlapping peptides. The N-terminus is blocked and thus not susceptible to Edman degradation. The amino-acid composition of the tryptic N-terminal peptide corresponds to that of the cytoplasmatic Cu-Zn superoxide dismutases of other mammals investigated. The chromatographic behaviour of these N-terminal peptides on a reversed phase C18 column is also identical, thus suggesting also for the rabbit Cu-Zn superoxide dismutase the N-terminal sequence Ac-Ala-Thr-Lys. The C-terminus was demonstrated to have the sequence -Ile-Ala-Pro by enzymatic degradation with carboxypeptidase Y. The complete amino-acid sequence of the rabbit Cu-Zn superoxide dismutase consists of 152 amino-acids and shows the expected homology to other Cu-Zn enzymes published so far. The aspartate and six histidine residues known to complex the metal ions are conserved at homologous positions. This also applies for the arginine residue near the C-terminus which is supposed to direct the anionic superoxide radical towards the active centre of the enzyme. The amino acid sequence of the rabbit Cu-Zn superoxide dismutase corresponds to those of other mammals in more than 80% of its amino-acid residues. From a total of 152 amino-acid residues the rabbit shares with rat 128, with mouse 130, with horse 127, with pig 126/127, with cattle 130 and with man 131 amino acids in homologous positions. However the Cu-Zn superoxide dismutases of closely related mammals like rats and mice differ in only five amino acid residues of their sequence. A phylogenetic closer relatedness between lagomorphs and rodents than between other orders of mammals, could not be derived from the sequence data given. Rather rodents and lagomorphs are to be considered as two evolutionary independent orders of mammals.
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PMID:The amino-acid sequence of rabbit Cu-Zn superoxide dismutase. 321 53

The spike glycoprotein of influenza C/Johannesburg/1/66 was isolated in a soluble form by digestion of MDCK cell-grown virions with bromelain. The whole ectodomain of the glycoprotein could be recovered with an apparent molecular weight of 75,000 daltons determined in SDS-PAGE. Comparison to Triton X-100-isolated glycoprotein revealed that a C-terminal peptide of 3000-4500 daltons must have remained in the viral membrane. When purified by sucrose density gradient centrifugation the glycoprotein sedimented with a sedimentation coefficient of 10 S, indicating a molecular weight of 206,000 daltons, which is consistent with a trimeric structure of the spike molecule. The trimeric form was stabilized in sucrose gradients by Ca2+ ions. Bromelain digestion of virions with uncleaved glycoprotein, grown in MDCK cells without trypsin, produced two disulphide-linked subunits with similar electrophoretic mobilities in SDS-PAGE to the biologically active glycoprotein. The smaller subunit differed from the product cleaved in vivo (gp 30) by the presence of an additional arginine residue at the N-terminus. The soluble glycoprotein appears to possess both receptor-binding and receptor-destroying enzyme activities, as isolated glycoprotein inhibited hemagglutination of intact influenza C virions and showed RDE activity in an in vitro test. Glycoprotein exposed to low pH, which was sensitive to trypsin digestion, also demonstrated both these biological activities. Glycoprotein-mediated hemolysis could not be observed.
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PMID:Isolation of the influenza C virus glycoprotein in a soluble form by bromelain digestion. 341 82

Limited proteolysis of rabbit skeletal muscle AMP deaminase (AMP aminohydrolase, EC 3.5.4.6) with trypsin results in conversion of the enzyme to a form which is no longer inhibited by ATP and exhibits hyperbolic kinetics even at low K+ concentration and in the absence of ADP. The interaction with troponin T from white skeletal muscle or with the phosphorylated 42-residue N-terminal peptide of troponin T restores in the trypsin-treated AMP deaminase the sensitivity to adenine nucleotides and increases the KA for K+ activation of the enzyme from 1 mM to 12 mM, this effect being diametrically opposite to that exerted by limited proteolysis on the native enzyme. Treatment of the N-terminal peptide of troponin T with alkaline phosphatase abolishes the modulating properties of the peptide, suggesting that phosphorylation-dephosphorylation processes may be involved in the regulation of the enzyme.
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PMID:Interaction with troponin T from white skeletal muscle restores in white skeletal muscle AMP deaminase those allosteric properties removed by limited proteolysis. 396 31

Protein E of the tick-borne encephalitis virus (TBEV) (strain Sofin) was treated with purified trypsin in 1% Triton X-100, and the peptides thus obtained were separated by micro-column reversed-phase chromatography. Four of the purified peptides were sequenced, their structures being in accordance with the nucleotide sequence of the viral protein E gene. Amino acid sequences of peptides deduced from the cDNA primary structure are: Ser-Val-Leu-Ile-Pro-Ser-His-Ala-Gln-Gly-Asp-Leu-Thr-Gly-Arg (N-terminal peptide of protein E); Thr-Glu-Gly-Ala-Gln-Asn-Trp-Asn-Ala-Glu-Arg: Trp-Leu-Glu-Gly-Asp-Ser-Leu-Arg; Leu-Val-Glu-Phe-Gly-Ala-Pro-His-Ala-Val-Lys.
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PMID:[Amino acid sequence of various tryptic peptides of the envelope protein of the tick-borne encephalitis virus]. 408 24

Infection of BHK 21 cells by vesicular stomatitis virus (VSV) results in the intracellular synthesis of the five viral proteins which are easily detectable in polyacrylamide gels after short labeling periods with [35S]methionine. In addition, a 6th prominent radioactive protein band appears intracellularly in VSV-infected BHK cells. This additional polypeptide is also coded by the viral genome, because it is immunoprecipitated by antibodies against viral particles and more specifically by antibodies against purified G-protein. We propose to call this derivative of the G-protein Gsi-protein (short intracellular G-protein). It is associated with intracellular membranes and has an apparent mol. wt. of 58 000. Both G- and Gsi-protein have the same kinetics of appearance in the cell. The ratio of G-:Gsi-protein in BHK 21 cells is approximately 85:15. The mol. wt. difference of approximately 6000 daltons between G- and Gsi-protein is not due to variations in the degree of glycosylation because trypsin digestions of both [3H]mannose-labeled glycoproteins gave rise to identical glycopeptide patterns. Incubation of microsomes with trypsin demonstrates that Gsi-protein is protected in its full length by intracellular membranes. Gsi-protein is lacking an extended carboxy-terminal region of the viral G-protein sequence because it is not modified by palmitic acid and is not immunprecipitated by specific antibodies against a C-terminal peptide of the G-protein. Limited proteolysis by endoproteinase arg C indicates that the structure of Gsi-protein is very similar to the shedded form of the G-protein which has been previously described in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intracellular appearance of a glycoprotein in VSV-infected BHK cells lacking the membrane-anchoring oligopeptide of the viral G-protein. 608 25

Four mouse monoclonal antibodies directed against the red cell membrane protein glycophorin A have been isolated and characterized. They are produced by hybridomas derived from SP2/0 myeloma cells and spleen cells from Biozzi mice immunized with a mixture of human erythrocytes from homozygous blood group M and N individuals. These antibodies recognize and bind to purified glycophorin A and to glycophorin on the red cell surface. All are of the IgGl, kappa light chain subclass and bind to determinants presented on the 39 amino acid, trypsin-sensitive, N-terminal peptide of glycophorin A. Three display differential specificities for the two allelic forms of glycophorin A; two are exquisitely specific for the M-form and one preferentially binds the N-form. Treatment of red cells with neuraminidase, which removes N-acetylneuraminic acid from glycophorin A, abolishes the binding of these three antibodies. The binding of the N-specific antibody is also sensitive to modification of the amino-terminal residue of the antigen. The fourth antibody binds equally well to both the M- and N-forms as well as to neuraminidase-treated red cells; thus it recognizes a public, N-acetylneuraminic acid independent glycophorin A determinant.
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PMID:Monoclonal antibodies specific for the M- and N-forms of human glycophorin A. 619 36

When scallop S1(+LC) (formerly called CaMg S1) is digested by trypsin, the heavy chain degrades while the two light chains remain complexed to each other and a peptide fragment of the heavy chain. The three components of the complex comigrate during electrophoresis under nondissociating conditions and can be purified by chromatography and concentrated by precipitation with ammonium sulphate in the presence of millimolar calcium ions. The truncated regulatory light chain remains associated with the binary complex consisting of the peptide and essential light chain as long as divalent cations are present; in the presence of EDTA it dissociates. This behaviour of the light chains-peptide complex mimics that of the intact molecule. The effect of bound light chains and bound actin on the susceptibility to tryptic digestion was studied using scallop S1(+LC) and S1(-LC) (EDTA S1 according to previous nomenclature). The heavy chains of both types of S1 are labile and have two main sites susceptible to proteolysis. Tryptic digestion on site A produces an N-terminal peptide of around 70 000 and a C-terminal 24 000 fragment from S1(+LC) and a 20 000 C-terminal fragment from S1(-LC); the latter is prone to further proteolysis. Thus S1(-LC), produced in the absence of bound regulatory light chain is shorter on the C-terminal end. Proteolysis on site A abolishes actin-activated ATPase activity; the latter is prevented by digesting acto-S1. The rate of tryptic digestion on site B is somewhat slower than on site A; when either S1 is split at this site an N-terminal 63 000 peptide is produced. The corresponding C-terminal peptide can be obtained from acto-S1 when hydrolysis on site A is prevented; this is estimated as around 31 000 derived from S1(+LC) and 28 000 derived from S1(-LC). The results are compared with similar experiments where vertebrate subfragments were digested by trypsin and the possible localization of the light-chain binding peptide in the intact heavy chain is discussed.
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PMID:Tryptic digestion of scallop S1: evidence for a complex between the two light-chains and a heavy-chain peptide. 623 96


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