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Table 3 Substrate-dependent specific activities of purified AdhE and AdhB of Thermoanaerobacter sp. strain X514

From: Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514

  AdhE AdhB
Substrate [U mg–1] [U mg–1]
  NAD+ NAD+ NADP+
Alcohol oxidation* − CoA  + CoA   
Ethanol 2.2 3.3 0.1 8.8
2-Propanol n. d n. d 5.3 51.4
1-Propanol 2.0 4.8 n. d n. d
1-Butanol 1.4 2.3 n. d n. d
2-Butanol 0 n. d n. d n. d
2,3-Butanediol 0 n. d n. d n. d
Aldehyde/ketone reduction NADH NADPH NADH NADPH
Acetaldehyde 46.0 7.0 4.1 33.3
Propionaldehyde 45.3 n. d 0.9 29.9
Isobutyraldehyde 40.6 n. d 0.6 38.0
Butyraldehyde 29.7 n. d 0 24.4
Phenylacetaldehyde n. d n. d 0 2.3
Acetone 0 n. d 0.7 29.4
2,3-Butanedione 0 n. d 1.9 34.7
Aldehyde oxidation (+ CoA) NAD+ NADP+ NAD+ NADP+
Acetaldehyde 10.5 1.1 0.1 0
Propionaldehyde 8.4 n. d n. d n. d
Isobutyraldehyde 7.3 n. d n. d n. d
Butyraldehyde 10.6 n. d n. d n. d
  1. Activities were determined in 50 mM Tris buffer (pH 7.5) supplemented with 2 mM DTE and 4 µM resazurin. Alcohol (200–500 mM) or aldehyde (10–50 mM) oxidation was determined with NAD(P)+ (2 mM) as electron acceptor, in the presence or absence of coenzyme A (0.2 mM; AdhE). Aldehyde or ketone (10 mM) reduction to alcohols was determined with NAD(P)H (0.5 mM) as electron donor; and absorption at 340 nm was measured. For details, please see “Methods” section. One unit (U) refers to one µmol of NADP+ reduced or NAD(P)H oxidized per minute. n. d.: not determined
  2. *Please note that CoA-dependent alcohol oxidation requires the reduction of 2 mol of NAD(P)+