Effect of the HP-β-CD/substrate molar ratio on the catalytic reaction. Reactions were carried out in 50 mM sodium phosphate buffer (pH 7.0) at 40°C with a substrate concentration of 20 mM. HP-β-CD was added according to the molar HP-β-CD/substrate ratio (0.05 to 2.0). The relative activity was tested when the reaction had proceeded for 10 min, and the e.e. value was determined when the conversion rate reached 40%. The actual activity at 100% was 33.8 U/mL.