Table 2. Substrate Binding Affinity and Kinetic Properties of Selected MCL-Oxidizing P450 Variants^a.

variant	selectivity	KD (μM)b	product formation ratec	coupling efficiencyd
FL#62	C2-selective	61 ± 3	49 ± 1	36%
V-F10	C2-selective	88 ± 18	28 ± 5	18%
VIII-B1	C14-selective	nd	2 ± 0.1	3%
V-H10	C14-selective	590 ± 90	7 ± 1	7%
V-H10(A87I)	C14-selective	1250 ± 54	3 ± 0.5	3%
V-H10 (R47C,A87I)	C14-selective	365 ± 53	13 ± 3	10%
		(128 ± 8)e	(22 ± 4)e	(15%)e

^aMean values and standard deviations are calculated from triplicate experiments conducted at room temperature.

^bDerived from heme spin shift experiments; nd = not determined.

^cRates are measured over initial 60 s in 50 mM potassium phosphate (KPi) (pH 8.0) and expressed as mole product per mole P450 per minute.

^dRatio between product formation rate and NADPH consumption rate in the presence of MCL.

^eReactions in 1 M KPi buffer (pH 8.0).