S.-W. Han, J.-S. Shin
Table 2 One-pot
Entry
Substrate
Reaction
Reaction
time (h)
Conversionb (%)
Reaction
eeD (%)
deracemization of dl-1b-d
conditionsa
yieldc (%)
1
2
3
4
5
6
dl-1b
dl-1b
dl-1c
dl-1c
dl-1d
dl-1d
A
B
A
B
A
B
28
9
28
20
28
48
82
>99
81
>99
10
88
90
93
85
95
66
90
82
>99
80
>99
19
88
aA: 50 mM dl-1b–d, 50 mM 3, 1 mM NAD+, 14 U mL−1 AlaDH, 16 U mL−1 ARTAmut and 5 U mL−1
NOX. B: 10 mM dl-1b-d, 50 mM 3, 1 mM NAD+, 140 U mL−1 AlaDH, 8 U mL−1 ARTAmut and
5 U mL−1 NOX
bConversion represents a ratio of consumption of l-amino acid to the initial amount of l-amino acid, i.e.
([l-amino acid]t=0 −[l-amino acid]t)/[l-amino acid]t=0
cReaction yield=[d-amino acid]t/[dl-amino acid]t=0
Acknowledgements This work was funded by the National Research
(i.e. less than 1% activity relative to that of l-1a). Under
the reaction conditions, 10 mM dl-1b and dl-1c were com-
pletely deracemized and led to 93 and 95% reaction yields
of the desired d-amino acid products with >99% eeD after 9
and 20 h, respectively (Table 2; entries 2 and 4). However,
l-1d was not completely converted to d-1d even after 48-h
reaction and the resulting eeD was 88% (entry 6).
Foundation of Korea under the Basic Science Research Program
(2016R1A2B400840). We thank Mrs Sae-Rom Park for technical
assistance in the cloning of NOX.
Compliance with Ethical Standards
Conflict of interest All authors declare that they have no conflict of
interest to disclose.
For demonstration of practical applicability, we per-
formed preparative-scale deracemization of dl-1a in a
25 mL reaction mixture under the reaction conditions of
100 mM dl-1a, 100 mM 3, 1 mM NAD+, 70 U mL−1 AlaDH
(73 µM), 1.6 U mL−1 ARTAmut (200 µM) and 10 U mL−1
NOX (2.4 µM). Complete deracemization was achieved after
24 h, leading to 95% reaction yield and >99% eeD of d-1a.
Product isolation using cation-exchange chromatography led
to recovery of optically pure d-1a (0.11 g, 52% isolation
yield). The purified d-1a was structurally characterized by
1H NMR, 13C NMR and MS (see Supplementary Materials).
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