Aldehyde dismutase activity of human liver alcohol dehydrogenase

FEBS Letters

Höög, Jan-Olov¹  Svensson, Stefan¹  Cronholm, Tomas¹  Lundsjö, Anders¹ 

[1] Department of Medical Biochemistry and Biophysics, Berzelius Laboratory, Karolinska Institutet, S-171 77 Stockholm, Sweden

关键词: Alcohol dehydrogenase;    Dismutation;    Recombinant protein;    Gas chromatography-mass spectrometry;   

DOI  :  10.1016/0014-5793(96)00954-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Human alcohol dehydrogenases of class I and class II but not class III catalyse NAD⁺-dependent aldehyde oxidation in addition to the NADH-dependent aldehyde reduction. The two reactions are coupled, i.e. the enzymes display dismutase activity. Dismutase activity of recombinantly expressed human class I isozymes β ₁ β ₁ and γ ₂ γ ₂, class II and class III alcohol dehydrogenases was assayed with butanal as substrate by gas chromatographic-mass spectrometric quantitations of butanol and butyric acid. The class I γ ₂ γ ₂ isozyme showed a pronounced dismutase activity with a high k _cat, 1300 min⁻¹, and a moderate K _m, 1.2 mM. The class I β ₁ β ₁ isozyme and the class II alcohol dehydrogenase showed moderate catalytic efficiencies for dismutase activity with lower k _cat values, 60–75 min⁻¹. 4-Methylpyrazole, a potent class I ADH inhibitor, inhibited the class I dismutation completely, but cyanamide, an inhibitor of mitochondrial aldehyde dehydrogenase, did not affect the dismutation. The dismutase reaction might be important for metabolism of aldehydes during inhibition or lack of mitochondrial aldehyde dehydrogenase activity.

【 授权许可】

Unknown