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)

An immunological study of anthranilate synthetase (ASase) has been initiated using quantitative precipitation, enzyme neutralization, and immunodiffusion methods. Cross-reactivity of anthranilate synthetase-anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase (ASase-PRTase) from Escherichia coli, Klebsiella aerogenes, and Salmonella typhimurium and ASase from Serratia marcescens and Pseudomonas putida was detected with antibodies to ?E. coli trypsin-treated ASase. Cross-reactivity of antigens was also obtained with S. marcescens anti-ASase. Indices of dissimilarity verified the overall structural similarity of ASase-PRTase from E. coli, K. aerogenes, and S. typhimurium and the divergence from S. marcescens ASase. Further divergence of these enzymes from ASase in B. subtilis and P. putida was apparent. Precipitation of ASase components I and II (ASase CoI and ASase CoII) was obtained using anti-ASase or antiserum fractionated to contain component-specific antibodies. Anti-ASase inhibited enzyme activity to binding to determinants on both subunits. Anti-ASase CoI inhibited the ammonia-dependent reaction and interfered with amide transfer from glutaminyl-ASase CoII. Anti-ASase CoII inhibited the glutamine reaction by blocking amide transfer. Enzyme neutralization experiments indicate more conservation of determinants at the active site region of ASase CoII compared to ASase CoI in the enterobacteria. A particulate form of ASase-PRTase in E. coli, K. aerogenes, and S. typhimurium could be distinguished by quantitative precipitation and immunodiffusion.
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PMID:Immunological study of anthranilate synthetase. 5 Mar 16

Apolipoprotein glutamine I (apoLP-Gln-I or apoA-I) is the major protein constituent of the human plasma high density lipoproteins. Cleavage of this protein with cyanogen bromide yields four fragments, designated in the order of elution from Bio-Gel P-30 as CNBr I, II, III, and IV. In the first paper in this series, the amino acid sequence of the NH2-terminal fragment, CNBr II, is reported. In the present study, CNBr IV, III, and I, containing, respectively, 25, 36, and 94 amino acids were sequenced by conventional means. To establish the alignment of the cyanogen bromide fragments, apoLP-Gln-I was digested with trypsin and two of the three methionine-containing tryptic peptides were isolated. The amino acid sequence of apoLP-Gln-I is as follows: (see article). With the complete amino acid sequence available, a CPK space-filling model of apoLP-Gln-I was constructed. The protein was placed into an alpha helical conformation wherever the primary structure permitted. Thirteen helical regions were identified. These regions account for 70% of the amino acid residues of the protein. Each helix is characterized as having two faces (amphipathic). One is a polar face that occupies approximately 180 degrees of the surface of the helix and the other is a hydrophobic face that occupies the other 180 degrees of the helical surface. Similar amphipathic helices have been identified previously in the other lipoprotein-proteins that have known sequences. It is suggested that the amphipathic helical regions of apoLP-Gln-I are important in the binding of phospholipids in high density lipoproteins.
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PMID:The primary structure of human plasma high density apolipoprotein glutamine I (ApoA-I). II. The amino acid sequence and alignment of cyanogen bromide fragments IV, III, and I. 16 50

The amino acid sequence of a 51-residue tryptic peptide of citraconylated [1-14C]carboxamidomethyl-labeled Escherichia coli GMP synthetase was determined by sequenator analyses of the intact peptide and fragments obtained by cleavage of the peptide with cyanogen bromide, trypsin, and Staphylcoccus aureus strain V8 protease. The cysteine residue of this peptide fragment is essential for glutamine-dependent GMP synthesis activity and is implicated in formation of a hypothetical covalent glutamyl-enzyme intermediate. There is essentially cysteine-containing regions of two other glutamine amidotransferases, Pseudomonas putida anthranilate synthetase Component II and chicken liver formylglycinamide ribonucleotide amidotransferase. There is, however, a cluster of amino acids with "antipathy" for helix formation and a "nonessential" cysteine of anthranilate synthetase Component II.
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PMID:Amino acid sequence of a peptide containing an essential cysteine residue of Escherichia coli GMP synthetase. 21 34

Gliadin, subsequently treated with pepsin, trypsin and pancreatic extract was further digested by small-intestinal mucosal homogenates from 10 control or 8 coeliac children. The amino acids liberated in the incubation mixture were measured and corrected for mucosal damage. In accordance with the data from the literature on adults, the total amount of amino acids released from gliadin peptides by the intestinal mucosa from children with active coeliac disease is significantly lower than that by the mucosa from control subjects. Qualitatively, however, no significant differences for the individual amino acids are observed with the exception of glutamine and proline, so that damaged coeliac mucosa liberates relatively more glutamine but less proline.
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PMID:Digestion of gliadin peptides by intestinal mucosa from control or coeliac children. 37 39

The single polypeptide chain of about 460 amino acids of porcine pancreatic lipase (EC 3.1.1.3) has been fragmented into five peptides by cyanogen bromide cleavage [Rovery, M., Bianchetta, J. & Guidoni, A. (1973) Biochim. Biophys. Acta, 328, 391--395]. The sequence of the first three cyanogen bromide peptides (CNI, CNII, CNIII), including a total of 234 amino acids, was fully elucidated. Automatic or manual Edman degradation was performed on the different peptides. Fragmentations of the CN peptides were accomplished by digestions with trypsin (after citraconylation or 1,2-cyclohexanedione treatment), chymotrypsin and Staphylococcus aureus external protease. Hydrolysis of unreduced material by pepsin and thermolysin, performed in order to determine the S-S bridge positions, provided useful overlapping peptides. The glycan moiety of lipase is bound to Asn-166. The non-essential tyrosine specifically blocked by diisopropylphosphorofluoridate is Tyr-49 in a cluster of asparagine and glutamine residues. The existence of a highly hydrophobic sequence (206--217) at the C terminus of the CNII fragment is noteworthy.
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PMID:Porcine pancreatic lipase. Sequence of the first 234 amino acids of the peptide chain. 38 Sep 92

The glutamate dehydrogenase from a single human liver has been studied. The subunit size was found to be 55,200 +/- 1,500 by sedimentation equilibrium. The partial specific volume is 0.732 as calculated from the amino acid composition. The sequence was determined by isolation of peptides after cyanogen bromide (CNBr) cleavage; the fraction containing the largest peptides was hydrolyzed by trypsin after maleylation. Studies on these peptides accounted for 454 residues of the 505 residues that are presumably present in the protein. For the 51 residues that were not represented in isolated peptides, we have tentatively assumed that the sequence is the same as that of the bovine enzyme. Methionine and arginine residues in these peptides could be placed on the basis of the specificity of cleavage by CNBr or trypsin. In all, 349 residues were placed in sequence, and were aligned by homology with the corresponding peptides of the bovine and chicken enzymes. From the present information, there are 24 known differences in sequence between the human and bovine enzymes and 41 between the human and chicken enzymes. In addition, the human enzyme contains 4 additional residues at the NH2 terminus as compared to the bovine enzyme. In a peptide from the human enzyme, an additional residue, isoleucine 385, was detected by automated Edman degradation. Reinvestigation of the bovine sequence demonstrated that this residue is also present in the bovine enzyme (and presumably in the chicken enzyme also). Residue 384 of the bovine enzyme, previously reported as Glx has now been shown to be glutamine.
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PMID:Partial amino acid sequence of the glutamate dehydrogenase of human liver and a revision of the sequence of the bovine enzyme. 42 60

The N-terminal procollagen peptide of the pN alpha 1(I) chain from dermatosparactic calf skin contains 139 amino acid residues. For the determination of the amino acid sequence the procollagen peptide was treated with pyroglutamate aminopeptidase, protease from Staphylococcus aureus V8 and trypsin. The fragments obtained were separated by molecular sieve and ion-exchange chromatography and submitted to automated Edman degradation. The procollagen peptide consists of three segments, an N-terminal globular domain which contains all the cysteine residues and most of the hydrophobic residues present in the entire peptide, a triple helical part with a relatively high content of proline and hydroxyproline, and a short nonhelical region which forms the connection to the nonhelical region of the alpha 1(I) chain and which contains the proline-glutamine bond specifically split by the N-terminal procollagen peptidase during conversion of procollagen to collagen.
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PMID:Amino acid sequence of the aminoterminal segment of dermatosparactic calf-skin procollagen type I. 48 18

The primary specificity of porcine pancreatic kallikrein is directed predominantly against arginyl and much less so against lysyl bonds. In addition, the enzyme exhibits pronounced secondary specificity for a bulky residue, preferentially phenylalanine, in position P2 of substrates. This feature is found also in porcine submandibular and urinary and in human urinary kallikrein, but not in bovine trypsin. Residues in P3 and P1' and P1' to P3' also affect hydrolysis by pancreatic kallikrein distinctly more than tryptic hydrolysis. The hexapeptide Pro-Phe-Arg-Ser-Val-Gln with the sequence of bovine kininogen around the C-terminus of kinin contains all the structural elements essential for the interaction with kallikrein, and even glutamine appears dispensable. In contrast to ester models for this site, peptidyl methionine esters with the structure of kininogen towards the N-terminus of kinin, notably bulky leucine in P2, are very poor kallikrein substrates, and appear to be of no value as models for the cleavage of kininogen under formation of kallidin.
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PMID:Substrate specificity of porcine pancreatic kallikrein. 49 15

Human fibrinogen was clotted under conditions that promote latent factor XIII activity and in the presence of a radioactive substitute cross-linking donor ([14C]glycine ethyl ester). The labeled fibrin was reduced and alkylated in the presence of 6 M guanidinium chloride. After dialysis and freeze-drying, the preparation was separated into its constituent polypeptide subunits by chromatography on (carboxymethyl)cellulose in the presence of 8 M urea. Under the incorporation conditions used, the radioactivity was limited to gamma chains (one donor molecule/chain) and alpha chains (two donor molecules/chain). The labeled alpha chains were digested with cyanogen bromide and fractionated on Sephadex G-50. All the radioactivity was found in a fragment previously designated H alpha CNI, the largest of the cyanogen bromide fragments in the alpha chain. The fragment was further fragmented by digestion with plasmin, trypsin, chymotrypsin, and/or staphylococcal protease. The incorporated radioactivity was found to reside in equal amounts at two different sites located 38 residues apart. These were determined to be positions 88 and 126 in H alpha CNI, which correspond to glutamine-328 and glutamine-366 in the alpha chain.
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PMID:Amino acid sequence studies on the alpha chain of human fibrinogen. Exact location of cross-linking acceptor sites. 51 45

Soybean inhibitor D-II is an inhibitor of bovine trypsin. Sequence analysis was carried out on the reduced and S-carboxymethylated protein by conventional methods to establish the complete amino acid sequence. The sequence of D-II indicated high homology with other legume inhibitors, but it was unique because of the occurrence of identical residues (arginine) at both of the reactive sites. This structure is thought to reflect that of a prototype double-headed inhibitor. The possible evolutionary process of the legume double-headed inhibitors is discussed on this basis. Comparison with another soybean inhibitor C-II suggested that a single methionine (C-II)-glutamine (D-II) replacement at the P2'position resulted in the loss of alpha-chymotrypsin inhibitory activity of D-II. The results of a hydrogen peroxide oxidation experiment on C-II supported this suggestion. The sequence of the amino-terminal 21 residues of inhibitor E-I was determined using a sequentor. It was shown that this inhibitor lacks the amino-terminal nine residues of D-II.
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PMID:Studies on soybean trypsin inhibitors, XII. Linear sequences of two soybean double-headed trypsin inhibitors, D-II and E-I. 64 Oct 33


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