Construction of an electric power-steering apparatus is achieved that, by stably suppressing backlash of an output shaft 6a of an electric motor 5 over a long period of time, is able to stably reduce vibration and strange noise that occurs during operation. The improved halohydrin epoxidase of the present invention consists of an amino acid sequence in which a specific amino acid substitution mutation is introduced into an amino acid sequence of a wild-type halohydrin epoxidase comprising predetermined amino acid sequences I and II. A refrigerant flows through the first plenum and the second plenum to remove heat from the stator. 11, UWB, USB wireless andor any similar interface.