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

---

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

We previously found a trypsin-like proteinase which momentarily appears immediately before DNA synthesis in the cell cycle of Escherichia coli synchronized by phosphate starvation and which is closely related to the initiation of DNA replication (Kato, M., Irisawa, T., Morimoto, Y. and Muramatu, M., unpublished results). The proteinase was named proteinase In. It was purified approximately 2880-fold with a recovery of 15%. The isolated enzyme appeared homogeneous by gel filtration and electrophoresis. Its molecular mass was estimated by analytical gel filtration and SDS/PAGE as approximately 66 kDa. The isoelectric point of proteinase In is 4.9 and its optimal pH is approximately 9. Although protein In hydrolyzes fluorogenic substrate for trypsin, its hydrolytic activity seems markedly affected by amino-acid sequence lying towards the N-terminal from the P1 (lysine, arginine) residue. The proteinase does not hydrolyze N2-benzoyl-D,L-arginine-4-nitronanilide and fluorogenic substrates for chymotrypsin and elastase. The proteinase activity is inhibited by leupeptin, antipain and 4-nitrophenyl 4-guanidinobenzoate, but the effects of tosyl-L-lysine chloromethane, diisopropylfluorophosphate, benzamidine and pentamidine isethionate on the proteinase activity are weak or not inhibitory. Its activity is strongly affected in the presence of NaCl and KCl, and at a concentration of 1.5 M, these increase the activity 14-fold and 13-fold, respectively, above that without salt. Proteinase In was strongly inhibited by various esters of trans-4-guanidinomethylcyclohexanecarboxylic acid, and their inhibitory effects were roughly correlated with those on growth of E. coli. Proteinase activity was found in the cytoplasmic fraction.
...
PMID:Purification and characterization of proteinase In, a trypsin-like proteinase, in Escherichia coli. 133 54

Fimbriae are important in the adherence of many bacterial species to the surfaces they eventually colonize. Porphyromonas (Bacteroides) gingivalis fimbriae appear to mediate adherence to oral epithelial cells and the pellicle-coated tooth surface. The role and contribution of fimbriae in the binding of P. gingivalis to hydroxyapatite (HAP) coated with saliva as a model for the pellicle-coated tooth surface were investigated. 3H-labeled P. gingivalis or the radioiodinated purified fimbriae were incubated with 2 mg of HAP beads coated with whole human saliva (sHAP) and layered on 100% Percoll to separate unbound from sHAP-bound components. The radioactivity of the washed beads was a measure of the bound components. The binding of P. gingivalis 2561 (381) cells and that of purified fimbriae were concentration dependent and saturable at approximately 10(8) cells and 40 micrograms of fimbriae added, respectively. The addition of fimbriae inhibited binding of P. gingivalis to sHAP beads by 65%, while the 75-kDa protein, which is another major surface component of P. gingivalis 2561, did not show significant inhibition, suggesting that the fimbriae are important in adherence. Encapsulated and sparsely fimbriated P. gingivalis W50 did not bind to sHAP beads. On the basis of the predicted sequence of the fimbrillin, a structural subunit of fimbriae, a series of peptides were synthesized and used to localize the active fimbrillin domains involved in P. gingivalis adherence to sHAP beads. Peptides from the carboxyl-terminal one-third of the fimbrillin strongly inhibited P. gingivalis binding to sHAP beads. Active residues within the sequence of inhibitory peptide 226-245 (peptide containing residues 226 to 245) and peptide 293-306 were identified by using smaller fragments prepared either by trypsin cleavage of the peptide 226-245 or by synthesis of smaller segments of peptide 293-306. Hemagglutinin activity, lectinlike binding, and ionic interaction did not seem to be involved in this binding since lysine, arginine, carbohydrates, and calcium ions failed to affect the binding of P. gingivalis. The observation that poly-L-lysine, bovine serum albumin, and defatted bovine serum albumin, even at high concentrations, only partially blocked the binding of P. gingivalis indicates that hydrophobic interactions are not the major forces involved in P. gingivalis binding to sHAP beads. Protease inhibitors such as EDTA, leupeptin, pepstatin, 1,10-phenanthroline, and phenylmethylsulfonyl fluoride did not interfere with the binding of P. gingivalis. However, the binding of P. gingivalis to trypsin- or chymotrypsin-pretreated sHAP beads was reduced.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Synthetic peptides analogous to the fimbrillin sequence inhibit adherence of Porphyromonas gingivalis. 134 62

We have altered the amino acid at the center of the reactive site (methionine 73) of Streptomyces subtilisin inhibitor (SSI) by site-directed and cassette mutagenesis. Replacement by lysine or arginine resulted in trypsin inhibitory activity, replacement only by lysine gave inhibition of lysyl endopeptidase, and replacement by tyrosine or tryptophan resulted in inhibition of alpha-chymotrypsin. The four mutant SSIs retained their native activity against subtilisin BPN'. Thus by altering only one amino acid residue at the reactive site of SSI to the substrate specificity of the respective protease we could successfully change its inhibitory profile.
...
PMID:Alteration of the specificity of the Streptomyces subtilisin inhibitor by gene engineering. 136 38

The major inhibitor of trypsin in seeds of Prosopsis juliflora was purified by precipitation with ammonium sulphate, ion-exchange column chromatography on DEAE- and CM-Sepharose and preparative reverse phase HPLC on a Vydac C-18 column. The protein inhibited trypsin in the stoichiometric ratio of 1:1, but had only weak activity against chymotrypsin and did not inhibit human salivary or porcine pancreatic alpha-amylases. SDS-PAGE indicated that the inhibitor has a Mr of ca 20,000, and IEF-PAGE showed that the pI is 8.8. The complete amino acid sequence was determined by automatic degradation, and by DABITC/PITC microsequence analysis of peptides obtained from enzyme digestions of the reduced and S-carboxymethylated protein with trypsin, chymotrypsin, elastase, the Glu-specific protease from S. aureus and the Lys-specific protease from Lysobacter enzymogenes. The inhibitor consisted of two polypeptide chains, of 137 residues (alpha chain) and 38 residues (beta chain) linked together by a single disulphide bond. The amino acid sequence of the protein exhibited homology with a number of Kunitz proteinase inhibitors from other legume seeds, the bifunctional subtilisin/alpha-amylase inhibitors from cereals and the taste-modifying protein miraculin.
...
PMID:The complete amino acid sequence of the major Kunitz trypsin inhibitor from the seeds of Prosopsis juliflora. 136 92

Silkworm antitrypsin (sw-AT), which was thought to belong to serpin family, changed its behavior against denaturation after chymotryptic cleavage of a single peptide bond (Tyr-Val) two amino acids away from the reactive site for trypsin (Lys-Val). This chymotrypsin-modified sw-AT became resistant to denaturation by heat, sodium dodecyl sulfate, or guanidine hydrochloride, and this characteristic was evident in its circular dichroism spectrum. The modified sw-AT was also indigestible by S. aureus V8 protease. These facts should indicate a structural change from a stressed, unstable state to a stable one accompanying the cleavage of the single peptide bond in sw-AT. The stabilizing factor was in part attributed to the interaction of a COOH-terminal fragment (5 kDa) and an NH2-terminal one (36 kDa) in modified sw-AT.
...
PMID:Single site proteolysis in silkworm antitrypsin causes structural changes in behavior against denaturing reagents. 136 16

Poly-L-lysine with molecular masses of 3.3-290 kDa increased the amidolytic activities of leukocyte elastase and cathepsin G at low concentration, but had little effect on the activities of pancreatic elastase, alpha-chymotrypsin, plasmin and thrombin. Highly purified cathepsin G was obtained from column of EAH Sepharose 4B or Suc-L-Tyr-D-Leu-D-Val-pNA-Sepharose (affinity chromatography) by elution with poly-L-lysine solution (0.4 mg/ml, molecular weight (MW.) 290000 or 2.2 mg/ml, MW. 3300). Leukocyte elastase, adsorbed to Suc-L-Tyr-D-Leu-D-Val-pNA-Sepharose, was not eluted with poly-L-lysine solution. The amino acid composition of purified cathepsin G has been determined.
...
PMID:Application of poly-L-lysine to purification of leukocyte cathepsin G by affinity chromatography. 139 85

Enzymes hydrolyzing chymotrypsin synthetic substrate and trypsin synthetic substrate, referred to as Enzyme I and Enzyme II, respectively, were found in the envelope fraction of Capnocytophaga gingivalis (ATCC 33624). Detergent extraction of both enzymes were purified by gel filtration, ion exchange chromatography, and affinity chromatography. The Enzyme I was a serine-containing metallo enzyme with a molecular mass of 77 kDa. The molecular mass of the Enzyme II was 83 kDa, and it was inhibited by tosyl-L-lysine chloromethyl ketone and leupeptin, and thus may be related to trypsin.
...
PMID:Isolation and characterization of enzymes hydrolyzing chymotrypsin synthetic substrate (Enzyme I) and trypsin synthetic substrate (Enzyme II) from the envelope of Capnocytophaga gingivalis. 140 57

The oxidation of ascorbic acid leads to the formation of several compounds which are capable of reacting with protein amino groups via a Maillard reaction. Radioactivity from [1-14C]ascorbic acid was linearly incorporated into lens crystallins over a 10 day period in the presence of NaCNBH3. This rate of incorporation was 6-7-fold more rapid than that obtained with [14C]glucose under the same conditions. SDS-PAGE showed a linear incorporation into all the crystallin subunits. [1-14C]Ascorbic acid-label led alpha-crystallin was separated into its component A and B subunits, and each was digested with chymotrypsin. HPLC peptide analysis showed a differential labelling of the various lysine residues. Analysis of the peptides by mass spectrometry allowed the identification of the sites and the extent of modification. These values ranged from 6% for Lys-78 to 36% for Lys-11 in the A subunit and from 5% for Lys-82 to an average of 38% for the peptide containing Lys-166, Lys-174 and Lys-175 in the B subunit. Amino acid analysis demonstrated a single modification reaction producing N epsilon-(carboxymethyl)lysine. This agreed with the mass increase of 58 observed for each modified peptide.
...
PMID:Site-specific glycation of lens crystallins by ascorbic acid. 152 82

Trypsin (Tr) and chymotrypsin (Ch) have similar tertiary structures, yet Tr cleaves peptides at arginine and lysine residues and Ch prefers large hydrophobic residues. Although replacement of the S1 binding site of Tr with the analogous residues of Ch is sufficient to transfer Ch specificity for ester hydrolysis, specificity for amide hydrolysis is not transferred. Trypsin is converted to a Ch-like protease when the binding pocket alterations are further modified by exchange of the Ch surface loops 185 through 188 and 221 through 225 for the analogous Tr loops. These loops are not structural components of either the S1 binding site or the extended substrate binding sites. This mutant enzyme is equivalent to Ch in its catalytic rate, but its substrate binding is impaired. Like Ch, this mutant utilizes extended substrate binding to accelerate catalysis, and substrate discrimination occurs during the acylation step rather than in substrate binding.
...
PMID:Converting trypsin to chymotrypsin: the role of surface loops. 154 24

An enterotoxin produced by Bacteroides fragilis was purified to homogeneity and characterized as to its biological activity and basic molecular properties. Toxin preparations were prepared by growing B. fragilis VPI 13784 in brain heart infusion broth to early stationary phase, immediately precipitating the culture supernatant fluid with 70% ammonium sulfate, and stabilizing the precipitate with the protease inhibitor TPCK (tolylsulfonyl phenylalanyl chloromethyl ketone). The toxin was sequentially purified by anion-exchange chromatography on Q-Sepharose, hydrophobic interaction chromatography on phenyl-agarose, and high-resolution ion-exchange chromatography on Mono Q. The toxin appeared homogeneous as judged by polyacrylamide gel electrophoresis. The estimated molecular weight of the highly purified toxin as determined by gel filtration chromatography on Superose-12 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis is 19,000. It has an isoelectric point of approximately 4.5 and is stable at pHs 5 to 10. The purified toxin is stable at -20 and 4 degrees C and upon freeze-drying, but it is unstable at temperatures above 55 degrees C. It is sensitive to proteinase K and Streptomyces protease but is resistant to trypsin and chymotrypsin. The activity of the purified toxin is neutralized by antiserum to a toxigenic strain of B. fragilis but not by antiserum to nontoxigenic strains. N-terminal amino acid analysis reveal an unambiguous sequence of Ala-Val-Pro-Ser-Glu-Pro-Lys-Thr-Val-Tyr-Val-Ile-Xxx-Leu-Arg-Glu-Asn-Gly- Ser-Thr . The highly purified toxin induced a strong fluid accumulation response in the lamb ileal-loop assay as well as a cytotoxic response (cell rounding) on HT-29 colon carcinoma cells. Thus, the purified toxin can cause both enterotoxic and cytotoxic activities.
...
PMID:Purification and characterization of an enterotoxin from Bacteroides fragilis. 154 60


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---