tailieunhanh - Báo cáo khoa học: The specificity of alcohol dehydrogenase with cis-retinoids Activity with 11-cis-retinol and localization in retina

Studies inknockoutmice support the involvement of alcohol dehydrogenases ADH1 and ADH4 in retinoid metabolism, althoughkineticswithretinoids arenotknown for themouse , a roleof alcohol dehydrogenase (ADH) in the eye retinoid interconversions cannot be ascertained due to the lack of information on the kinetics with 11-cis-retinoids. We report here the kinetics of human ADH1B1, ADH1B2, ADH4, and mouse ADH1 and ADH4 with all-trans-, 7-cis-, 9-cis-, 11-cis- and 13-cis-isomers of retinol and retinal | Eur. J. Biochem. 271 1660-1670 2004 FEBS 2004 doi The specificity of alcohol dehydrogenase with ós-retinoids Activity with 11-ós-retinol and localization in retina Silvia Martras1 Rosana Alvarez2 Susana E Martinez1 Damaso Torres1 Oriol Gallego1 Gregg Duester3. B Jaume Farres1 Angel Rb de Lera2 and Xavier Pares1 1 Department of Biochemistry and Molecular Biology Universitat Autonoma de Barcelona Bellaterra Barcelona Spain 2Department of Organic Chemistry Universidad de Vigo Pontevedra Spain 3 OncoDevelopmental Biology Program Burnham Institute La Jolla CA USA Studies in knockout mice support the involvement of alcohol dehydrogenases ADH1 and ADH4 in retinoid metabolism although kinetics with retinoids are not known for the mouse enzymes. Moreover a role of alcohol dehydrogenase ADH in the eye retinoid interconversions cannot be ascertained due to the lack of information on the kinetics with 11-cis-retinoids. We report here the kinetics of human ADH1B1 ADH1B2 ADH4 and mouse ADH1 and ADH4 with alltrans- 7-cis- 9-cis- 11-cis- and 13-cis-isomers of retinol and retinal. These retinoids are substrates for all enzymes tested except the 13-cis isomers which are not used by ADH1. In general human and mouse ADH4 exhibit similar activity higher than that of ADH1 while mouse ADH1 is more efficient than the homologous human enzymes. All tested ADHs use 11-cis-retinoids efficiently. ADH4 shows much higher kcafKm values for 11-cis-retinol oxidation than for 11-cis-retinal reduction a unique property among mammalian ADHs for any alcohol aldehyde substrate pair. Docking simulations and the kinetic properties of the human ADH4 M141L mutant demonstrated that residue 141 in the middle region of the active site is essential for such ADH4 specificity. The distinct kinetics of ADH4with 11-cis-retinol its wide specificity with retinol isomers and its immunolocalization in several retinal cell layers including pigment epithelium support a role of this enzyme