Retinal dehydrogenase (RALDH)

Retinal dehydrogenase represents a family of NAD-dependent oxidoreductase enzymes responsible for converting retinal (vitamin A aldehyde) to retinoic acid, a critical morphogen regulating gene expression, tissue differentiation, and development. Structurally, these enzymes function as tetramers or dimers and are characterized by unique substrate access channels that confer selectivity for retinal over smaller aldehydes[1][7]. Three principal isoforms—ALDH1A1, ALDH1A2 (retinal dehydrogenase 2), and ALDH1A3—are differentially expressed in tissues such as embryonic structures, retina, testis, lung, and brain[4][8]. Their activity is essential not only for the visual cycle but also for the regulation of stem cell populations, embryonic pattern formation, and the enteric nervous system[7][8][10]. Dysfunction or dysregulation of retinal dehydrogenase activity is implicated in congenital malformations, certain neoplasms, and retinal degenerative disorders[2][5][8][10]. Note that therapeutic targeting is challenging due to critical developmental and homeostatic functions.

Other names

Retinaldehyde dehydrogenaseRALDHALDH1A1ALDH1A2ALDH1A3Aldehyde dehydrogenase family 1 member A1/A2/A3

Enzyme inhibition (prevents retinal oxidation and retinoic acid formation) and modulation of retinoic acid levels, affecting nuclear receptor signaling pathways.