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)

The sequence of three alcohol dehydrogenase alleloenzymes from the fruitfly Drosophila melanogaster has been determined by the sequencing of peptides produced by trypsin, chymotrypsin, thermolysin, pepsin and Staphylococcus aureus-V8-proteinase digestion. The amino acid sequence shows no obvious homology with the published sequences of the horse liver and yeast enzymes, and secondary structure prediction suggests that the nucleotide-binding domain is located in the N-terminal half of the molecule. The amino acid substitutions between AdhN-11 (a point mutation of AdhF), AdhS and AdhUF alleloenzymes were identified. AdhN-11 alcohol dehydrogenase differed from the other two by a glycine-14-(AdhS and AdhUF)-to-aspartic acid substitution, the AdhS enzyme from AdhN-11 and AdhUF enzymes by a threonine-192-(AdhN-11 and AdhUF)-to-lysine (AdhS) substitution and the AdhUF enzyme was found to differ by an alanine-45-(AdhS and AdhN-11)-to-aspartic acid (AdhUF) charge substitution and a 'silent' asparagine-8-(AdhS and AdhN-11)-to-alanine (AdhUF) substitution. Detailed sequence evidence has been deposited as Supplementary Publication SUP 50107 (36 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.
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PMID:The complete amino acid sequence of three alcohol dehydrogenase alleloenzymes (AdhN-11, AdhS and AdhUF) from the fruitfly Drosophila melanogaster. 682 73

The complete amino acid sequences and the disulfide arrangements of the two chains of human haptoglobin 1-1 were established. The alpha 1 and beta chains of haptoglobin contain 83 and 245 residues, respectively. Comparison of the primary structure of haptoglobin with that of the chymotrypsinogen family of serine proteases revealed a significant degree of chemical similarity. The probability was less than 10(-5) that the chemical similarity of the beta chain of haptoglobin to the proteases was due to chance. The amino acid sequence of the beta chain of haptoglobin is 29--33% identical to bovine trypsin, bovine chymotrypsin, porcine elastase, human thrombin, or human plasmin. Comparison of haptoglobin alpha 1 chain to activation peptide regions of the zymogens revealed an identity of 25% to the fifth "kringle" region of the activation peptide of plasminogen. The probability was less than 0.014 that this similarity was due to chance. These results strongly indicate haptoglobin to be a homolog of the chymotrypsinogen family of serine proteases. Alignment of the beta-chain sequence of haptoglobin to the serine proteases is remarkably consistent except for an insertion of 16 residues in the region corresponding to the methionyl loop of the serine proteases. The active-site residues typical of the serine proteases, histidine-57 and serine-195, are replaced in haptoglobin by lysine and alanine, respectively; however, aspartic acid-102 and the trypsin specificity, residue, aspartic acid-189, do occur in haptoglobin. Haptoglobin and the serine proteases represent a striking example of homologous proteins with different biological functions.
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PMID:Covalent structure of human haptoglobin: a serine protease homolog. 699 77

Two trypsin inhibitors from the seed of Acacia elata, a legume of the subfamily Mimosoideae, were isolated by affinity chromatography on trypsin-Sepharose 4B and separated by chromatography on SP-Sephadex C-25 and Sephadex G-100. The two inhibitors, with molecular weights of about 20 000, were composed of two polypeptide chains linked by a disulfide bond. The two inhibitors had essentially the same amino acid compositions and both contained four half-cystine residues, no methionine and were rich in aspartic acid, glutamic acid, glycine and leucine. The inhibitors had isoelectric points of 6.4 and 5.9. The inhibitors stoichiometrically inhibited trypsin in the molar ratio of 1:1, alpha-chymotrypsin was inhibited also in a 1:1 molar ratio but the binding of the enzyme by the inhibitor was weaker and the inhibitor-chymotrypsin complex dissociated during the assay. Both enzymes are probably inhibited at an identical site. Amino-terminal sequence analysis of the two polypeptide chains of the inhibitors revealed extensive homology with the trypsin inhibitor from the silk tree (another Mimosoideae legume); both these inhibitors are homologous with the soybean trypsin inhibitor (Kunitz).
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PMID:Acacia proteinase inhibitors. Purification and properties of the trypsin inhibitors from Acacia elata seed. 723 19

A new inhibitor of bovine alpha-chymotrypsin has been isolated from winged bean seed. The inhibitor was purified to homogeneity by affinity chromatography on chymotrypsin-Sepharose, following the removal of the trypsin inhibitors on trypsin-Sepharose. The inhibitor has a molecular weight of approx. 21,000 and amino acid analysis showed that it contains four half-cystine residues, lacks methionine, and is rich in aspartic acid, glutamic acid, valine and leucine. The inhibitor does not inhibit bovine trypsin in the standard inhibitor assay and does not bind to trypsin-Sepharose at ph 8.0. Inhibition data show that 1 mol of inhibitor inhibits 2 mol of alpha-chymotrypsin to form a 1:2 complex. The inhibition, however, is characterized by substrate induced dissociation of the complex and complete inhibition, even at high inhibitor concentration, is not attained. The inhibitor-chymotrypsin complex is stable at pH 8.0 and was isolated by gel-filtration on Sephadex G-100. An apparent molecular weight of approx. 70,000 was obtained for the complex, measured by gel filtration and ultracentrifugal analysis, consistent with a 1:2 molar stoichiometry.
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PMID:Isolation and properties of a chymotrypsin inhibitor from winged bean seed (Psophocarpus tetragonolobus (L) Dc.). 740 36

Pancreatic cDNA libraries from Atlantic salmon (Salmo salar) were constructed and screened with salmon trypsin-specific probes. Five clones containing near full-length transcripts were selected for further characterization. Comparison of deduced amino acid sequences revealed that all variants possessed the canonical serine protease catalytic triad, consisting of histidine, aspartic acid and serine residues, a substrate-binding pocket with aspartic acid at the bottom, and 12 cysteine residues comprising six disulphide bridges. Translation in vitro of one of the trypsin clones produced a protein with the expected molecular mass of 24.5 kDa. Three of the Atlantic salmon trypsins (SalTRP-I, SalTRP-IA and SalTRP-IB) possessed very similar sequences and may represent allelic variants encoded by the same gene focus; however, existence as tetraploid loci or isoloci where disomic inheritance is incomplete may also exist in Atlantic salmon and cannot be excluded. Two other trypsin clones (SalTRP-II and SalTRP-III) are probably encoded by separate gene loci. Analysis of genomic DNA by Southern blotting and hybridization to a trypsin probe showed a complex pattern, indicative of a large number of gene loci for trypsin in Atlantic salmon. The charged amino acid distribution showed that four of the Atlantic salmon trypsin clones encoded anionic forms of the enzyme, while the fifth clone represented a cationic variant. Multiple alignments of the Atlantic salmon trypsin sequences with trypsin, chymotrypsin and elastase from different species placed all Atlantic salmon sequences approximately equidistant from trypsins of other species. Interestingly, the distance between the anionic and cationic variants from Atlantic salmon was similar to the distance between salmon and mammalian trypsins, revealing an early separation of these two types of trypsin, possibly prior to the derivation of fish during evolution. A structural model based on X-ray diffraction studies of the salmon trypsin protein was very similar to that of the mammalian enzyme. All residues which differ in charge between anionic and cationic trypsins were located at exposed regions of the proteins.
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PMID:Molecular cloning and characterization of anionic and cationic variants of trypsin from Atlantic salmon. 755 23

Microtubule-associated protein (MAP) 1 consisting of MAP 1A and 1B was purified from rat brain by the poly-L-aspartic acid (PLAA) method. We found that MAP 1 bound to F-actin in vitro up to a molar ratio of MAP 1 to actin monomers of 1:10. The apparent binding constant was about 2.7 x 10(7) M-1. In contrast to the binding of MAP 2 or tau to F-actin, the binding of MAP 1 to F-actin did not affect the low-shear viscosity of actin filaments. Binding experiments performed using fragments of MAP 1, obtained by chymotrypsin digestion, indicated that MAP 1 included binding domains to F-actin that were different from those in microtubules and also two light chains (31 and 29 kDa) that were cosedimented with F-actin as well as with microtubules.
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PMID:Microtubule-associated proteins, MAP 1A and MAP 1B, interact with F-actin in vitro. 790 20

The effect of dietary fiber viscosity on apparent ileal nitrogen and amino acid digestibility, proteolytic enzyme activity and digestive organ weights was investigated. Eighteen growing rats were fed for 21 d purified casein-based diets containing carboxymethylcellulose (50 g/kg) of low (20 cP), medium (800 cP) and high (2000 cP) viscosity (LV, MV and HV treatment groups, respectively). Dietary fiber viscosity did not significantly affect apparent ileal (terminal 15 cm of the ileum) nitrogen or amino acid digestibility, trypsin or chymotrypsin activity in the small intestinal contents and pancreatic tissue, aminopeptidase-N activity in the small intestinal contents and tissue, or the weights of the stomach, pancreas, small or large intestines. Intragastric pepsin activity in LV rats was significantly higher than in MV or HV rats (P < 0.01), but fiber viscosity did not affect pepsin activity in the stomach tissue. The intragastric pH of the HV and MV rats was significantly higher than that for the LV rats (P < 0.01). The stomach contents (dry matter) of MV and HV rats were greater than in LV rats (P < 0.05). Delayed passage rate of the more viscous digesta may have resulted in greater absorption of amino acids, because the HV rats had a higher estimated true ileal digestibility than the LV animals for threonine, serine, aspartic acid, glutamic acid, histidine, tyrosine and phenylalanine.
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PMID:Dietary fiber viscosity and amino acid digestibility, proteolytic digestive enzyme activity and digestive organ weights in growing rats. 820 41

A protein proteinase inhibitor was purified from a seed extract of amaranth (Amaranthus hypochondriacus) by precipitation with (NH4)2SO4, gel-filtration chromatography, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography. It is a 69-amino acid protein with a high content of valine, arginine, and glutamic acid, but lacking in methionine. The inhibitor has a relative molecular weight of 7400 and an isoelectric point of 7.5. It is a serine proteinase inhibitor that recognizes chymotrypsin, trypsin, and trypsin-like proteinase activities extracted from larvae of the insect Prostephanus truncatus. This inhibitor belongs to the potato-I inhibitor family, showing the closest homology (59.5%) with the Lycopersicum peruvianum trypsin inhibitor, and (51%) with the proteinase inhibitor 5 extracted from the seeds of Cucurbita maxima. The position of the lysine-aspartic acid residues present in the active site of the amaranth inhibitor are found in almost the same relative position as in the inhibitor from C. maxima.
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PMID:Purification, characterization, and complete amino acid sequence of a trypsin inhibitor from amaranth (Amaranthus hypochondriacus) seeds. 829 Jun 33

Four isoinhibitors against bovine pancreatic trypsin were purified from Phaseolus vulgaris(cv. Tora-mame) seeds by extraction with water(pH 2.0), ammonium sulfate fractionation, gel chromatography on Sephacryl S-200, trypsin-Sepharose gel affinity chromatography, and chromatofocusing. They inhibit both trypsin and chymotrypsin strongly. Their molecular masses are 85 kDa, estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Their isoelectric points range 5.09 to 4.46. They are high in the content of aspartic acid, serine, proline, and half-cystine but low in valine, methionine, tyrosine, and phenylalanine. Tryptophan is absent from them completely. They are bound to both trypsin and chymotrypsin with equimolar ratio, and have separate and independent binding sites for both proteases. Chemical modification showed that the inhibitors are of lysine type.
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PMID:Characterization of trypsin inhibitors from Tora-mame seeds, one of the Japanese cultivars of Phaseolus vulgaris. 840 16

Protein-carboxyl O-methyltransferase (protein methylase II) transfers the methyl group from S-adenosyl-L-methionine (AdoMet) to the carboxyl side chains of the amino acids in the proteins. We have used the radiolabeled analogue of AdoMet, 8-azido-S-adenosyl-L-[methyl-3H]methionine (8-N3-Ado[methyl-3H]Met), to investigate the AdoMet binding site of protein methylase II. The incorporation of the photoaffinity label in the enzyme upon UV irradiation is highly specific. In the absence of UV irradiation or if the photoprobe is irradiated prior to its addition to the reaction mixture, no photoinsertion of the label occurs. Moreover, the presence of a competitive inhibitor of protein methylase II, S-adenosyl-L-homocysteine (AdoHcy), or the unlabeled AdoMet itself in the reaction mixture diminished labeling of the enzyme. Sequential digestion of the labeled enzyme with trypsin, chymotrypsin, and endoproteinase Glu-C yielded a modified and radiolabeled decapeptide. When compared with the reported primary amino acid sequence of protein methylase II from rat brain, the amino acid composition of the decapeptide matched residues 113-121. This segment forms the midpoint region of the enzyme (234 amino acid residues). An important characteristic of the sequence is the presence of two adjacent aspartic acid residues (Asp117-Asp118) which most likely provide the negative charge environment for the sulfonium moiety of the AdoMet molecule.
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PMID:Identification of the S-adenosyl-L-methionine binding site of protein-carboxyl O-methyltransferase using 8-azido-S-adenosyl-L-methionine. 844 66


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