RGD Reference Report - Immunocytochemical and biochemical demonstration of formaldhyde dehydrogenase (class III alcohol dehydrogenase) in the nucleus. - Rat Genome Database

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Immunocytochemical and biochemical demonstration of formaldhyde dehydrogenase (class III alcohol dehydrogenase) in the nucleus.

Authors: Iborra, FJ  Renau-Piqueras, J  Portoles, M  Boleda, MD  Guerri, C  Pares, X 
Citation: Iborra FJ, etal., J Histochem Cytochem 1992 Dec;40(12):1865-78.
RGD ID: 1357171
Pubmed: PMID:1453005   (View Abstract at PubMed)

Alcohol dehydrogenase (ADH), the major enzyme catalyzing the biological oxidation of ethanol in mammals, includes four classes with very different capacities for ethanol oxidation. Class III ADH is present in all the tissues and is well conserved throughout evolution. This enzyme has a low activity with ethanol, is specific for the glutathione-dependent oxidation of formaldehyde, and is therefore a formaldehyde dehydrogenase (FALDH). Until now there have been few and conflicting studies concerning its intracellular distribution, which is important for the understanding of its role in cell function. In the present work we used biochemical and immunocytochemical methods to assess the distribution of FALDH in rat hepatocytes and astroglial cells. With the glutathione-dependent formaldehyde dehydrogenase assay, we found the highest activity in the cytosol of hepatocytes and brain cells (12 and 2.6 mU/mg protein, respectively), but nuclei also exhibited significant activity (1.16 and 2.1 mU/mg protein, respectively). The immunocytochemical results showed the presence of FALDH binding sites in both the cytoplasm and the nucleus of the different cell types studied. Whereas no specific gold particle labeling was seen associated with any cytoplasmic component, in the nucleus the particles were found mainly over condensed chromatin and interchromatin regions. Finally, the gold particle density over both the nucleus and cytoplasm was greater in differentiated than in proliferating astrocytes in primary culture. In contrast, class I ADH, primarily responsible for ethanol metabolism, was found only in the cytoplasm of hepatocytes. We propose that one of the functions of FALDH is to protect cell structures, including DNA, from the toxic effects of endogenous formaldehyde, which is an intermediate in many metabolic process.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
formaldehyde metabolic process  IDA 1357171 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Aldh3a2  (aldehyde dehydrogenase 3 family, member A2)

Objects referenced in this article
Gene Adh5 alcohol dehydrogenase 5 (class III), chi polypeptide Rattus norvegicus

Additional Information