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Table 1 Human ADH and ALDH family members involved in the metabolism of ethanol

From: Effect of the allelic variants of aldehyde dehydrogenase ALDH2*2 and alcohol dehydrogenase ADH1B*2on blood acetaldehyde concentrations

Enzyme

Class

Gene

locus

Allelic

Variant

Subunit

composition

K m

(mM)

V max

(U/mg)

Vmax/Km

(U/mg/mM)

ADH

I

ADH1A

 

αα

5.2

0.24

0.047

  

ADH1B

ADH1B*1

β1β1

0.016

0.18

12

   

ADH1B*2

β2β2

1.9

4.8

2.6

   

ADH1B*3

β3β3

53

3.2

0.060

  

ADH1C

ADH1C*1

γ1γ1

0.11

0.81

 
   

ADH1C*2

γ2γ2

0.061

0.47

 
 

II

ADH2

 

ππ

23

0.30

0.013

 

III

ADH3

 

χχ

3,400

0.83

 
 

IV

ADH4

 

μμ(σσ)

58

11

0.19

ALDH

I

ALDH1A1

 

Tetramer

0.033

0.63

19

 

II

ALDH2

ALDH2*1

Tetramer(E4)

0.00020

0.60

3,000

   

ALDH2*2

Tetramer(K4)

0.0046

0.017

3.6

  1. Enzyme activity was determined in 0.1M sodium phosphate, at pH 7.5 and 25°C. Samples contained 0.5 mM nicotinamide adenine dinucleotide (NAD; ie a cytosolic oxidised coenzyme concentration in hepatocytes), and various concentrations of ethanol for alcohol dehydrogenase (ADH) or of acetaldehyde for aldehyde dehydrogenase (ALDH). γ1γ1/γ2γ2 and χχ exhibit negative and positive cooperativity, respectively; hence they do not have a Km and the values shown are S0.5. Enzyme activity units (U) are expressed as micromoles NADH formed per minute under the assay conditions. Data are from Yin and Agarwal,[1] Yin et al [9]. and Lee et al [10].