Formaldehyde Dehydrogenase from Yeast and Plant

Abstract

Glutathione-dependent formaldehyde dehydrogenase, also known as class III alcohol dehydrogenase (class III ADH), is widely distributed in animals, plants and microorganisms (Uotila and Koivusalo, 1989). It is the main enzymatic system responsible for the formaldehyde elimination, although a role in the oxidation of long chain alcohols and ω-hydroxyfatty acids has also been proposed (Boleda et al. 1993). Class III ADH shows a well conserved structure and function throughout evolution, with 74% identities between the human and the octopus enzymes (Kaiser et al., 1993). However, differences exist between the catalytic constants of the enzymes isolated from different organisms (Uotila and Koivusalo, 1989; Fernández et al., 1995). In the present work we have studied the structure and function of class III ADH from two plants, Arabidopsis thaliana and pea (Pisum sativum), and from yeast (Saccharomyces cerevisiae), with the aim to characterize the kinetics of the enzymes and to relate their specific features with structural differences. The plant class III enzyme have been also compared with the classical alcohol dehydrogenase from plants, that we call class P (Shafqat et al, 1996), to establish functional and structural relationships between the two plant enzymes. Finally, the use of yeast has allowed the study of the physiological importance of the enzyme, by preparing a strain defective in class III ADH.