Summary: Aldehyde Dehydrogenase Assay provides a fluorescence-based method for detecting ALDH activity in tissue homogenates, cell culture samples, and purified ALDH preparations. In the assay, ALDH catalyzes the oxidation of acetaldehyde to acetic acid, along with the concomitant reduction of NAD+ to NADH. NADH reacts with the fluorometric developer to yield a highly fluorescent product which can be analyzed with an excitation wavelength of 530-540 nm and an emission wavelength of 585-595 nm.