Biosynthesis and Metabolism of Retinoic Acid: Roles of CRBP and CRABP in Retinoic Acid: Roles of CRBP and CRABP in Retinoic Acid Homeostasis

摘要: The enzymes that constitute the pathway of retinoic acid biosynthesis and metabolism may recognize retinoid binding proteins as effectors substrates. Apocellular retinol-binding protein (CRBP) stimulates a bile-salt independent membrane-bound retinyl ester hydrolase resulting in hydrolysis endogenous esters formation holoCRBP. HoloCRBP delivers retinol to microsomal nicotin-amide-adenine dinucleotide phosphate-dependent dehydrogenase, protects it from artifactual oxidation denies cannot access retinol. retinal synthesized be transferred microsomes cytosol by CRBP. A cytosolic dehydrogenase has been purified produces generated presence CRBP complex CRBP-retinal itself. Thus, CRBP(type I) seems channel retinoids through reactions synthesis via series protein-protein interactions. Cellular acid-binding (type facilitates sequestering acting low Km substrate, thereby also modulating steady-state concentrations acid.