M. R. LakshmananH. ChansangJ. A. OlsonMahidol University2018-03-122018-03-121972-12-01Journal of Lipid Research. Vol.13, No.4 (1972), 477-482002222752-s2.0-0015480054https://repository.li.mahidol.ac.th/handle/20.500.14594/9996Carotene 15,15' dioxygenase, which oxidizes carotenoids to retinal, has been purified up to 200 fold from rabbit intestine by ammonium sulfate fractionation, heat treatment, and acetone precipitation. With β apo 10' carotenol as the substrate, the purified enzyme has a pH optimum of 7.8, a K(m) of 6.7 x 10 -5 M, and a V(max) at 37° C of 9 nmoles of retinal/mg protein/hr. The purified enzyme is inhibited by ferrous ion chelating agents such as α,α' dipyridyl and o phenanthroline, and by sulfhydryl binding agents such as iodoacetamide, N ethylmaleimide, and p chloromercuribenzoate. The latter inhibitory effects are reversed by reduced glutathione. The cleavage of β apo 10' carotenol is competitively inhibited by its acetylenic analog, 15,15' dehydro β apo 10' carotenol. The enzyme is present in the intestinal mucosa of several mammals, the chicken, the tortoise, and a freshwater fish, but it is absent from cat intestinal tissue.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyArticleSCOPUS