African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12235

Full Length Research Paper

In vitro inhibition of the paraoxonase from human serum with sulfonamide

Selma Sinan
Balikesir University, Science and Art Faculty, Department of Biology/Biochemistry Section, 10145 Balikesir, Turkey.
Email: [email protected]

  •  Accepted: 01 February 2008
  •  Published: 04 March 2008



This study was conducted to determine the in vitro effects of sulfonamide on human serum paraoxonase (PON1) activity. The enzyme was purified by two-step using ammonium sulfate precipitation and sepharose-4B-L-tyrosine-1-napthylamine hydrophobic interaction chromatography. Sulfonamide was an effective inhibitor on purified human serum PON1 activity for phenylacetate and paraoxon as substrates with IC50 values of 0.22 and 0.81 mM, respectively. The kinetics of interaction of sulfonamide with the purified enzyme indicated a different inhibition pattern for two substrates. Sulfonamide showed a non-competitive inhibition with Ki of 0.0037 ± 0.0009 mM for phenylacetate and competitive inhibition with Ki of 0.0057 ± 0.0002 mM for paraoxon.


Key words: Paraoxonase, sulfonamide, inhibition, in vitro.