Chiral switch of enzymatic ketone reduction by addition of γ-cyclodextrin

We report a chiral switch in the configuration of 1-(p-methoxyphenyl)-propan-2-ol, synthesized in aqueous media by ketoreductase in the presence of high concentration of γ-CD. NMR, ECD and fluorescence spectrometry were used in the effort to explain this unexpected effect. A comparison has been made between the catalytic activity of the enzyme and α-helix content in the conformation and it has been observed that enzyme is most active at the maximum α-helix content. The β-sheet content and random coil conformation in the enzyme were found to be dependent on cyclodextrin concentration.