Semi-rational engineering an aldo–keto reductase for stereocomplementary reduction of α-keto amide compounds

Table 2 Enantioselectivity and conversion of iolS and double mutants toward ONDPA^a

Variants	ee (%)^b	Conv. (%)	Favored enantiomer
WT	76.1 ± 0.6	60.5 ± 0.5	S
I57F/F126I	94.3 ± 0.7	98.4 ± 0.8	S
I57Y/F126I	92.6 ± 1.3	95.3 ± 0.6	S
I57H/F126I	90.0 ± 0.4	83.0 ± 0.5	S
I57F/F126L	97.6 ± 0.4	98.5 ± 0.6	S
I57Y/F126L	94.2 ± 0.5	96.4 ± 0.4	S
I57H/F126L	93.7 ± 0.6	93.2 ± 0.4	S
N21A/F126A	99.9 ± 0.1	99.9 ± 0.2	R
N21S/F126A	99.9 ± 0.1	98.2 ± 0.4	R

^aReaction condition: 4 mM substrate 1a, 200 mM glucose and 0.1 g wet whole-cell in potassium phosphate buffer (100 mM, pH 7.0, 500 μL) at 30 °C. Experiments were conducted in duplicate
^bThe ee values were measured by chiral HPLC; the absolute configuration was determined by comparing the retention times with literature data
^cConversions were determined by chiral HPLC analysis

ISSN: 1475-2859