has role has part vitamin A A group of fat-soluble retinoids produced via metabolism of provitamin A carotenoids. Vitamin A is involved in immune function, vision, reproduction, and cellular communication. CHEBI:12777 Wikipedia:Vitamin_A chebi_ontology all-trans-retinoic acid all-trans-retinol all-trans-retinal fat-soluble vitamin metabolite retinoid all-trans-retinyl ester