WANG Meng-Liang, YUE Zhu
(Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China)
Abstract: An NADP(H)-dependent carbonyl reductase was purified from Rhodobacter sphaeroides in this study. First, cells produce disrupted by ultrasonic treatment at 4℃.The enzyme was purified through ammonium sulfate, DEAE-Sephadex A-25 from cell-extract. The enzyme gave a single band on SDS-PAGE. The relative molecular weight of the enzyme was estimated to be 37 kD. Reaction system with asymmetric reduction of ketones was established and optimized. The result shows the optimum pH and temperature for reduction were 8 and 37℃, respectively. The enzyme is stable at pH between 7 and 9, and the temperature stability was low. The apparent Michaelis-Menten constant (Km) and maximum reaction rate (Vmax) for acetophenone were 0.26 mmol/L and 2.4 μmol/ (min·mg), respectively. The enzyme can catalyze acetophenone to product corresponding S-alcohols mainly. The yield and the enantiomeric excess values (ee) of the reduction products was 58.5% andup to 99%. So, the enzyme is a potential catalyzer. Along with proposing hydrogenase regeneration system and bacteriochlorin regenerationsystem, further investigation onenzyme-catalyzed combining with coenzyme regeneration lays the foundation for enzyme-catalyzed industry in the future.
Key words: Rhodobacter sphaeroides;carbonyl reductase; acetophenon
E-mail: mlwang@sxu.edu.cn
Journal of Molecular Catalysis, Vol. 24, Issue 1, 2010, 87~92
