Table 6.

Alkoxyresorufin binding by wild-type CYP102A1 and CYP102A1 M11 mutants

Substrate	K D (µM)a
	Methoxyresorufin	n-Butoxyresorufin	n-Heptoxyresorufin	Benzyloxyresorufin
CYP102A1 (wild type)	8.4 ± 1.4	1.6 ± 0.2	22 ± 6.4	2.7 ± 0.4
CYP102A1 M11 Ala87	4.0 ± 0.5	1.1 ± 0.1	4.9 ± 0.4	1.4 ± 0.3
CYP102A2 M11 Val87	2.4 ± 0.2	0.8 ± 0.1	1.4 ± 0.2	1.8 ± 0.3

^aDissociation constants were determined by difference spectroscopy using 2 µM enzyme in 100 mM potassium phosphate buffer, pH 7.4, titrated with a solution of substrate. All substrates produced a type I binding spectrum with a peak at 390 nm and trough at 419 nm. The data for the absorbance at 419 nm minus the absorbance at 390 were corrected for dilution and fitted to an equation for a bimolecular association reaction to obtain the dissociation constant