Mayssaa E. Abdalah1, Ghazi M. Aziz2 and Ali H. Adʼhiah3
1Clinical Laboratory Sciences Department, College of Pharmacy, Al-Mustansiriyah University
2 Biotechnology Department, College of Science, University of Baghdad
3Tropical-Biological Research Unit, College of Science, University of Baghdad
The study aimed to extract, purify and characterize dihydrofolate reductase (DHFR). The DHFR was extracted from mice liver with specific activity of 0.114 U/mg protein, and partially purified by precipitation using ammonium sulfate (45-85%) and gel filtration chromatography using Sephadex G-75 with specific activity of 1.2U/mg protein, purification fold of 10.53 and 67.5% yield. A maximum activity was reached at pH 5.5 – 6.0, while it was stable at pH 4.5-7.5 for 15 minutes. The highest DHFR activity was observed at 25-30°C, and it maintained its original activity when incubated at 25-35°C, but completely lost its activity after incubation for the same time at 60°C. The effect of some chlorides (potassium chloride, sodium chloride, calcium chloride, mercuric chloride, silver chloride and magnesium chloride), EDTA, 2-mercaptoethanol, sodium dodecyl sulfate (SDS) and urea on the remaining activity of purified DHFR was also determined, and their effect was dependent on the type of material and dose.
KEYWORDS: Dihydrofolate Reductase, characterization, activators, inhibitors.