7-Dehydrocholesterol

White powder. Soluble in ethanol, chloroform or ethyl acetate. Slightly soluble in DMSO. Insoluble in water. Precursor of cholesterol and vitamin D3. It is reduced to cholesterol by the enzyme 3beta-hydroxysterol-Delta7-reductase (DHCR7) in the last step of cholesterol biosynthesis. Mutations in the gene encoding DHCR7 lead to increased levels of 7-DHC and the neurodevelopmental syndrome Smith-Lemli-Opitz syndrome (SLOS). 7-DHC is used as a biomarker for SLOS screenings. Inhibits human fibroblast sphingomyelinase. Shown to have cytotoxic effects on melanoma cells. In skin, photolysis of 7-DHC by ultraviolet light produces vitamin D3. UV/Vis: lambdamax 271, 282, 293nm.