SUMMARY PARAGRAPH for FDH1
About glutathione-dependent formaldehyde oxidation
Formaldehyde is formed by oxidative demethylation reactions in many plants and methylotrophic organisms, but Saccharomyces cerevisiae is a nonmethylotrophic yeast and cannot metabolize methanol to formaldehyde. However, S. cerevisiae is exposed to exogenous formaldehyde from plant material or in polluted air and water.
Concentrations of formaldehyde of 1mM or higher are cytostatic or cytotoxic to haploid wild-type cells. Any free formaldehyde in vivo spontaneously reacts with glutathione to form S-hydroxymethylglutathione (2, 3, 4). The level of enzymes involved in the degradation of formaldehyde, such as Sfa1p and Yjl068p, determine the level of formaldehyde toxicity, and cells overproducing Sfa1p are resistant to formaldehyde and null mutants in either sfa1 or yjl068c are hypersensitive to formaldehyde. Sfa1p is induced in response to chemicals such as formaldehyde (FA), ethanol and methyl methanesulphonate, and Yjl068p is also induced in response to chemical stresses (5, 3, 4, 6, 7, 8, 9).
Formate dehydrogenase is encoded by FDH1/YOR388C and FDH2. In some strain backgrounds of S. cerevisiae, FDH2 is encoded by a continuous open reading frame comprised of YPL275W and YPL276W. However, in the systematic sequence of S288C, FDH2 is represented by these two separate open reading frames due to an in frame stop codon (1).
Last updated: 2007-10-04