Loss of Carotene-9′,10′-Monooxygenase Expression Increases Serum and Tissue Lycopene Concentrations in Lycopene-Fed Mice

Two enzymes have been identified for the oxidative metabolism of carotenoids in mammals Carotene-15 15 monooxygenase (CMO I) primarily centrally cleaves beta beta-carotene to form vitamin A We hypothesize that carotene-9' 10 monooxygenase (CMO II) plays a key role in metabolism of acyclic nonprovitamin A carotenoids such as lycopene We investigated carotenoid bioaccumulation in young adult male wild-type (WT) mice or mice lacking CMO-II (CM II KO) Mice were fed an AIN 93G diet or identical diets supplemented with 10% tomato powder 130 mg lycopene/kg diet (10% lycopene beadlets) or placebo beadlets for 4 or 30 d Lycopene preferentially accumulated in CMO-II KO mouse tissues and serum compared with WT mouse tissues beta-Carotene preferentially accumulated in some CMO-II KO mouse tissues compared with WT mouse tissues Relative tissue mRNA expression of CMO-I and CMO-II was differentially expressed in mouse tissues and CMO-II but not CMO-I was expressed in mouse prostate In conclusion the loss of CMO-II expression leads to increased serum and tissue concentrations of lycopene in tomato-fed mice J Nutr 140 2134-2138 2010