Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclophylins are members of a class of proteins with peptidyl-prolyl cis-trans isomerase activity. These enzymes bind the immunosuppressive agent, cyclosporin A (CsA), which acts as a competitive inhibitor. The peptidyl-prolyl cis-trans isomerase from Bacillus subtilis (PPIase) was purified to homogeneity in a 4-step purification procedure, which resulted in a 100-fold protein purification with a yield of 5%. Coomassie blue-stained SDS-PAGE revealed a single band of about 18 kDa. PPIase activity was determined using synthetic peptides as substrates in a 2-step reaction coupled to chymotrypsin. Treatment of Bacillus subtilis PPIase by CsA revealed an inhibition constant of Ki = 175 nM, which differs from cyclophilin of enterobacteria such as E. coli or Salmonella typhimurium and is in the range of human enzymes.
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PMID:Peptidyl-prolyl cis-trans isomerase from Bacillus subtilis. A prokaryotic enzyme that is highly sensitive to cyclosporin A. 151 92

Peptidyl-prolyl cis-trans isomerase was extracted from pig kidney cortex and partially purified. Enzyme activity was monitored against the cis-trans isomerization of succinyl-Ala-Ala-Pro-Phe-methylcoumaryl amide by means of a two-step process using chymotrypsin as the trans cleaving activity. The in vitro refolding of denatured type III collagen, which is rate-limited by the cis-trans isomerization of peptide bonds, was studied in the presence of peptidyl-prolyl cis-trans isomerase by optical rotatory dispersion and by resistance to tryptic digestion. A 3-fold increase in the initial rate of folding was observed compared to the uncatalyzed refolding. This rate increase is comparable to the rate increase found for the CT-phase in the refolding of urea-denatured ribonuclease A, but it is smaller than the increase in the rate of isomerization of succinyl-Ala-Ala-Pro-Phe-methylcoumarylamide.
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PMID:The influence of peptidyl-prolyl cis-trans isomerase on the in vitro folding of type III collagen. 331 29

The 29-kDa FK506 binding protein (FKBP) gene is the only peptidyl-prolyl cis-trans isomerase (PPIase) gene in the genome of Pyrococcus horikoshii. We characterized the function of this FKBP (PhFKBP29) and used it to increase the production yield of soluble recombinant protein in Escherichia coli. The PPIase activity (k(cat)/K(m)) of PhFKBP29 was found to be much lower than that of other archaeal 16- to 18-kDa FKBPs by a chymotrypsin-coupled assay of the oligo-peptidyl substrate at 15 degrees C. Besides this low PPIase activity, PhFKBP29 showed chaperone-like protein folding activity which enhanced the refolding yield of chemically unfolded rhodanese in vitro. In addition, it suppressed thermal protein aggregation in a temperature range of 45 to 100 degrees C. When the PhFKBP29 gene was coexpressed with the recombinant Fab fragment gene of the anti-hen egg lysozyme antibody in the cytoplasm of E. coli, whose expressed product tended to form an inactive aggregate in E. coli, it improved the yield of the soluble Fab fragments with antibody specificity. PhFKBP29 exerted protein folding and aggregation suppression in E. coli cells.
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PMID:FK506 binding protein from the hyperthermophilic archaeon Pyrococcus horikoshii suppresses the aggregation of proteins in Escherichia coli. 1182 79