Purification of Paraoxonase (PON) from Sun Flower (Helianthus annuus) and Effects of Some Chemicals on Paraoxonase Activity In vitro
Nazan Demir *
Department of Chemistry, Faculty of Science, Mugla University, 48000, Mugla, Turkey.
Hayrunnisa Nadaroglu
Department of Food Technology, Erzurum Vocational Training School, Ataturk University, 25240, Erzurum, Turkey.
Yasar Demir
Department of Chemistry, Faculty of Science, Mugla University, 48000, Mugla, Turkey and Department of Chemistry, Faculty of Science,, University of Mehmet Akif Ersoy, 15000, Burdur, Turkey.
*Author to whom correspondence should be addressed.
Abstract
Aims: In this study, paraoxonase (PON) enzyme was purified from mature seeds of sun flower by using affinity chromatography (Sepharose-4B-L-tyrosine-1-naphthylamine) and the effects of some chemicals were tested on paraoxonase activity as in vitro.
Methodology: Paraoxonase was firstly purified from sun flower (Helianthus annuus). This enzyme was purified as 427-fold. SDS-polyacrylamide electrophoresis of the enzyme indicates a single protein staining band with an apparent Mr of 35 kDa. The kinetic properties of the purified enzyme were determined.
Results: The enzyme exhibits high activity at broad pH (pH 5.0-9.0) and temperature (40 and 70ºC). The purified enzyme remains stable at 4ºC for more than 1 year. Paraoxonase is mostly stable at 40ºC. The activity of the enzyme decreases to 55% at a temperature of 60ºC when the treatment was given for a period of 1h. Optimum pH of the purified enzyme was 7.0 and its optimum temperature was 40ºC. Using paraoxon as a substrate, the enzyme shows maximum activity (Vmax) of 7.84μmol.L.min-1 with its corresponding Km value of 0.317 mM. The activities was strongly inhibited by Hg2+, Fe3+, β-mercaptoethanol, dithioerythritol, SDS and EDTA while Cu2+ slightly activates the enzyme activity. As judged by catalytic efficiencies, paraoxon is the preferred substrate.
Conclusion: The present study shows that PON purified from sun flower (Helianthus annuus) is stable at wide range of pH and temperature and in the presence of some metal ions.
Keywords: Paraoxonase, purification, sun flower (Helianthus annuus), metal ions