1.14.13.B28 delL151-E156 the Km value of the mutant is about 2times lower than that of the wild-type. -, 725874 1.14.13.B28 F310A/A320Q site-directed mutagenesis, the mutant exhibits a 30 mV positive shift in redox potential for the FeIII/FeII couple compared with wild-type P450st due to weakening of the electron-donating effect (push effect) of the proximal thiolate in the mutant. This result indicates that the electron density around the heme is decreased, and thus the Lewis acidity of the heme is expected to be increased. Mutant F310A/A320Q maintains higher thermal stability than typical P450s -, 744870