Glutathione S-Transferase: Purification and Characterization of from Cherry Laurel (Prunus laurocerasus L.) and the Investigation In Vitro Effects of Some Metal Ions and Organic Compounds on Enzyme Activity

Abstract

In this study, the cherry laurel flesh fruit was purified to obtain glutathione S-transferase, a well-known antioxidant enzyme. Enzyme purification was performed using two separate processes: gel filtration and affinity chromatography. The sodium dodecyl sulfate electrophoresis method was used for determining enzyme purity. The optimum pH, optimum temperature, optimum ionic strength, stable pH, and KM and Vmax values for glutathione and 1-chloro-2,4-dinitrobenzene were obtained for the enzyme as follows: 7.0 in the K-phosphate buffer, 30 °C, 0.125 M, 6.5 in the K-phosphate buffer, 0.344 mM, 0.89 mM, and 0.098 EU/ml, 0.214 EU/ml. Lineweaver-Burk graphs were used to examine the in vitro enzyme activity in order to determine the inhibitory effects of some metal ions such as Cd2+, Ni2+, Cu2+, and Mg2+ and organic compounds such as sodium dodecyl sulfate (SDS), ascorbic acid (vitamin C), benzoic acid, and ethylenediaminetetraacetic acid (EDTA). The IC50 and Ki values for each of the metal ions and organic molecules were calculated. According to the results, Ca2+ metal ion and sodium dodecyl sulfate compounds were found to be the best inhibitor with a Ki value of 0.06 ± 0.04 and 0.20 ± 0.27, respectively.