Abstract
The metabolism of all-trans- and 9-cis-retinol/retinaldehyde has been investigated with focus on the activities of human, mouse and rat alcohol dehydrogenase 2 (ADH2), an intriguing enzyme with apparently different functions in human and rodents. Kinetic constants were determined with an HPLC method and a structural approach was implemented by in silico substrate dockings. For human ADH2, the determined Km values ranged from 0.05 to 0.3 μM and kcat values from 2.3 to 17.6 min-1, while the catalytic efficiency for 9-cis-retinol showed the highest value for any substrate. In contrast, poor activities were detected for the rodent enzymes. A mouse ADH2 mutant (ADH2Pro47His) was studied that resembles the human ADH2 setup. This mutation increased the retinoid activity up to 100-fold. The K m values of human ADH2 are the lowest among all known human retinol dehydrogenases, which clearly support a role in hepatic retinol oxidation at physiological concentrations. © 2007 Birkhäuser Verlag.
Original language | English |
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Pages (from-to) | 498-505 |
Journal | Cellular and Molecular Life Sciences |
Volume | 64 |
DOIs | |
Publication status | Published - 1 Feb 2007 |
Keywords
- Alcohol dehydrogenase
- Computer modeling
- Kinetic constant
- Retinaldehyde
- Retinol
- Substrate docking