Funció biològica i relacions estructura-funció en la família de les alcohol deshidrogenases

Alcohol dehydrogenase (ADH) constitutes a large family of related enzymes, extensively distributed in nature. These enzymes have been gruuped in classes, on the basis of their primary structure and kinetic properties. Although all ADHs reversibly oxidize alcohols, their substrate specificity and, therefore, their biological function, considerably change between classes. In the present project we will continue the studies on the structural and functional characterization of the class III and class IV ADH from different species. Class IV is present in epithelia, and it is characteristic on stomach mucosa. It is the most active ADH, with high kcat and Km values, and we are going to identify the residues responsible for these properties by site-directed mutagenesis. We will also study the structure of the human class IV gene, to understand the regulation of its expression. By means of immunohistochemical and \i in situ\i0 hybridization techniques we will study the detailed localization of class IV in the rat tissues, speccially in brain. On the other hand, class III in the cell nucleus. To know the role of class III in plants, we will study the enzyme in the \i Arabidopsis Thaliana\i0 . This enzyme will be expressed in a ADH class-III strain of yeast and the substrate specifity will be checked with plant alcohols. We will study the localiztion of the enzyme in the \i Arabidopsis\i0 cell types, and the capacity of the plant in taking and metabolizing formaldehyde, at both the whole plant and cell culture levels, in order to determine the possible detoxicating role of plants against the environmental formaldehyde.