Retinoids metabolism, cellular retinoid binding

The cellular metabolism of retinoids involves the interaction of several enzymes together with a number of retinoid-binding proteins44 64 (Fig. 3). While these binding proteins have been well described in mammals, little is known about their properties in fish, although orthologues of the mammalian proteins do exist29,55. Retinol can be metabolized to retinal and, in turn, be irreversibly converted to RA in tissues that... 

Napoli, J. L. 2000. A Gene Knockont Corroborates the Integral Function of Cellular Retinol-Binding Protein in Retinoid Metabolism. NutrRev 58, no 8 230-6. 

Ross, A C. (1993) Cellular metabolism and activation of retinoids roles of cellular retinoid-binding proteins FASEB J 7,317-327... 

Retinoid activities can also be modulated by the cellular retinoic acid-binding proteins (CRABPs) I and II. These proteins bind the natural retinoid trans-RA and potentiate its metabolic oxidation at the 4-position. ( )-4-[2-(3,5-Di-f-butylphenyl)propenyl]benzoic acid (CD55), which does not bind to CRABP and cannot be metabolized at its position corresponding to the 4-position of trans-RA, is far more potent than trans-RA in inducing the differentiation of HL-60 leukemia cells [43]. 

---