Characterization of a robust anti-Prelog short-chain dehydrogenase/reductase ChKRED20 from Chryseobacterium sp. CA49

ChKRED20 is a short-chain dehydrogenase/reductase (SDR) cloned from Chryseobacterium sp. CA49 for the anti-Prelog bioreduction of 3,5-bis(trifluoromethyl)acetophenone to produce the chiral alcohol intermediate for aprepitant. Purified ChKRED20 showed broad pH adaptability and stability with 91% of the maximal activity retained at pH 10.0. The temperature dependence of activity reached the maxima at 50 °C. Its half-lives of thermal inactivation were 163 and 9.8 h at 40 °C and 50 °C, respectively. The enzyme was resistant to a variety of metal ions, additives, and organic solvents. The enzymatic activity could be enhanced by the addition of particular metal ions or detergents to up to 168%. ChKRED20 also displayed good activity and excellent anti-Prelog stereoselectivity toward a spectrum of acetophenone derivatives, providing chiral alcohols with >99% ee for the majority of the substrates.