1. Faculty of Pharmaceutical Sciences and School of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
2. Department of Biochemistry, Saitama University, Urawa, Saitama, 338, Japan
3. Central Technical Research Laboratory, Nippon Oil Company, Ltd., 8 Chidori-cho, Naka-ku, Yokohama 231, Japan