Table 2 Kinetic Parameters of D2HDH in 4 M KCl for NADPH and NADH using 2-ketohexanoic acid as substrate and for 2-ketohexanoic acid using NADPH or NADH as cofactor

From: Potassium binding by carbonyl clusters, halophilic adaptation and catalysis of Haloferax mediterranei D-2-hydroxyacid dehydrogenase

 

KM (mM)

Vmax (U/mg)

KCAT (min-1)

KCAT/KM (mM-1 min-1)

NADPH

(2-ketohexanoic acid as substrate)

0.014 ± 0.004

2.5 ± 0.1

83 ± 4

5928

NADH

(2-ketohexanoic acid as substrate)

0.097 ± 0.018

4.4 ± 0.3

149 ± 10

1536

2-ketohexanoic acid

(NADPH as cofactor)

0.46 ± 0.03

2.5 ± 0.05

83 ± 2

180

2-ketohexanoic acid

(NADH as cofactor)

1.48 ± 0.16

3.8 ± 0.1

124 ± 4

84

  1. Assays were performed in 4 M KCl, 50 mM HEPES pH 8.0 with 0.05 - 20 mM 2-ketohexanoic acid 0.25 mM NADH; 0.05 - 4 mM 2-ketohexanoic acid, 0.25 mM NADPH; 0.025 - 0.3 mM NADPH, 4 mM 2-ketohexanoic acid or 0.05 - 0.3 mM NADH, 20 mM 2-ketohexanoic acid. KM and Vmax were calculated using http://www.ic50.tk/kmvmax.html
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