7-Dehydrocholesterol
- (3S, 10R, 13R, 17R ) -10.13 - dimethyl- 17 - (6- methylheptan- 2-yl) - 2,3,4,9,11,12,14,15,16,17 - decahydro - 1H- cyclopenta [ a] phenanthren -3-ol
- Cholesta -5 ,7-dien- 3β -ol
- Provitamin D3
White solid
Fixed
148-152 ° C
Template: Infobox chemical / molecular formula search available
7-dehydrocholesterol is a sterol which is the precursor of cholesterol, and Cholecalciferol (vitamin D3). 7- dehydrocholesterol was discovered by later Nobel Laureate Adolf Windaus.
Function
Formation of cholesterol
The enzyme 7- dehydrocholesterol reductase 7- dehydrocholesterol to cholesterol is reduced.
This enzyme is restricted in the Smith - Lemli -Opitz syndrome is caused by mutations in its activity differently. This means that in this syndrome 7 Dehydrocholesterolspiegel in the blood is high and the cholesterol is too low. Cholesterol in turn is used as a starting material for steroid hormones and bile acids.
Formation of vitamin D
Photolysis with UVB light of wavelengths 270-315 nm 7- dehydrocholesterol is first further converted into provitamin D3 and by thermal isomerization to vitamin D3. 7- dehydrocholesterol is found mainly in the stratum spinosum and stratum basale of the skin.