Organic-solvent enhancement is immediate and reversible. (a) Acetone and ethanol were used to dilute 5 μg/mL DLac into 1 μg/mL after 1 hr pre-incubation without organic solvents. (b) The organic-solvent enhancement of DLac activity was reversible. Acetone- or ethanol-pre-incubated with 5 μg/mL DLac was diluted to 1 μg/mL by organic-solvent–free buffer to evaluate reversibility (Tris-diluted). In comparison with reversible experiments, the corresponding organic solvent was used to dilute 5 μg/mL organic-solvent-pre-incubated DLac into 1 μg/mL (Acetone-diluted or Ethanol-diluted), respectively. One-fold of DLac activity is defined as the activity in absence of organic solvents. The significant difference (*) was set at P < 0.05 and the highly significant difference (**) was set at P < 0.001 in Student’s t-test, compared to their 0% organic solvent pre-incubation control. Data were shown as mean ± SD from at least three independent repeats.