Purification and characterization of NADPH-cytochrome P450 reductase from Lake Van fish liver microsomes and investigation of some chemical and metals' effects on the enzyme activity

Authors: MÜSLÜM KUZU, MEHMET ÇİFTCİ

Abstract: NADPH-cytochrome P450 reductase was purified from Lake Van fish liver microsomes by primary and secondary DEAE-cellulose column chromatograph with 20.46 \mu M/min/mg enzyme specific activities, 54.4% purification yield, and purification of 38-fold. The purity of the enzyme was established, and its monomer molecular weight was determined by SDS-polyacrylamide gel electrophoresis. SDS-PAGE results showed a single band and the molecular weight of NADPH-cytochrome P450 reductase was 70 kDa. In addition, optimum ionic strength, optimum pH, optimum temperature, and stable pH values were determined for the enzyme in the kinetic studies performed. K_M and V_{max} were determined for NADPH and cytochrome c. Effects of some metals ions, antibiotics, and some other drugs used in aquarium fisheries on the activity of the enzyme were investigated. IC50 values and K_i values of metals showing an inhibitory effect were calculated.

Keywords: NADPH-cytochrome P450 reductase, Lake Van fish, inhibition, metal, antibiotic

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