Aldehyde dehydrogenases: measurement of activities and protein levels.

Seventeen enzymes are currently viewed as belonging to the human aldehyde dehydrogenase superfamily, and all of them catalyze the pyridine nucleotide-dependent oxidation of aldehydes to acids. Depending on the specific aldehyde dehydrogenase, lack of sufficient catalytic activity (1) results in a gross pathological phenotype in the absence of any insult, or (2) is ordinarily of no consequence with respect to gross phenotype, but is of consequence when the organism is subjected to a relevant insult. Described in this unit are eight assays that can be used to (semi)quantify various in vitro aldehyde dehydrogenase protein and/or catalytic activity levels, and two that can be used to semiquantify various in situ aldehyde dehydrogenase protein and/or catalytic activity levels. Aldehyde dehydrogenases also catalyze the hydrolysis of esters; this unit includes an assay that can be used to quantify that catalytic activity as well. Preparation of test materials and of antibodies to the aldehyde dehydrogenases are described in three support protocols.