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.
- Alcohol dehydrogenase
- Computer modeling
- Kinetic constant
- Substrate docking
Hellgren, M., Strömberg, P., Gallego, O., Martras, S., Farrés, J., Persson, B., Parés, X., & Höög, J. O. (2007). Alcohol dehydrogenase 2 is a major hepatic enzyme for human retinol metabolism. Cellular and Molecular Life Sciences, 64, 498-505. https://doi.org/10.1007/s00018-007-6449-8