[Ketometabolite of vitamine A, its structure and enzymatic transformation].

The structure and enzymatic transformations of vitamin A keto-metabolite isolated from the rat liver were investigated. With the aid of physico-chemical methods, using isotopes 3/ and 18O, PMR and mass-spectrometry it was demonstrated that the metabolite was an ester of 4-keto-retinol with palmitic acid. The structure of 4-keto-retinal was confirmed by the chemical synthesis and by the enzymatic production of its derivatives.