1. Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chunchon 200-701, Korea
2. Department of Biological Sciences, College of Natural Sciences, Kangwon National University, Chunchon 200-701, Korea
3. College of Pharmacy, Ewha Womans University, Seoul 03760, Korea
4. Graduate School of Medicine, Kangwon National University, Chunchon 200-701, Korea