Effect of acetonitrile on Cynara cardunculus L. cardosin A stability

Anna V. Shnyrova, Claudia S. Oliveira, Ana C. Sarmento, Marlene T. Barros, Galina G. Zhadan, Manuel G. Roig, Valery L. Shnyrov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The kinetics of the structural changes affecting cardosin A, a plant aspartic proteinase (AP) from Cynara cardunculus L., in the presence of a mixture of acetonitrile (AN) in water (W) was studied. Incubation of cardosin A with 10% (v/v) AN resulted in a gradual increase in protein helicity, accompanied by changes in the tertiary structure, seen by changes in the intrinsic fluorescence of tryptophan. Differential scanning calorimetry (DSC) revealed that the temperature of denaturation of cardosin A decreased upon the addition of AN. With longer incubation times, the small chain of cardosin A denatured completely, consequent exposure of the single tryptophan residue accounting well for the observed spectral shift intrinsic fluorescence of the protein. Enzymatic activity assays demonstrated that the kinetically determined unfolding of the small chain of cardosin A does not result in loss of the activity of this enzyme.

Original languageEnglish
Pages (from-to)273-279
Number of pages7
JournalInternational Journal of Biological Macromolecules
Issue number4-5
Publication statusPublished - 15 Nov 2006


  • Cardosin A
  • Differential scanning calorimetry
  • Low organic medium catalysis
  • Protein stability
  • Water-acetonitrile mixture


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