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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)+