Vitamin D₃ Photosynthesis in Skin

7-Dehydrocholesterol → Previtamin D3 → Vitamin D3

概述

UV-B radiation (280–315 nm) converts 7-dehydrocholesterol in the skin to previtamin D₃ through a photochemical ring-opening reaction. Previtamin D₃ then thermally isomerizes to cholecalciferol (vitamin D₃). This is the primary source of vitamin D for most people and requires about 10–30 minutes of midday sun exposure.

日常示例

Spending 15–20 minutes in midday sunshine produces about 10,000–20,000 IU of vitamin D₃, far more than any food source.

工业重要性

全球超过10亿人存在维生素D缺乏，推动了维生素D₃补充剂和强化食品产业的快速发展，年市场规模数十亿美元。

属性

类型
Photochemical
可逆
否
能量
吸热

相关反应

Photochemical Smog Formation (NO₂ Photolysis) Photochromism of Spiropyran Chlorophyll Fluorescence Photodegradation of Methylene Blue by TiO₂ Photodissociation of Chlorine Gas Silver Bromide Photodecomposition Cis-Trans Isomerization of Retinal Photosynthesis Ozone Formation by UV Light Dye-Sensitized Solar Cell (Grätzel Cell)

Frequently Asked Questions

What is the equation for Vitamin D₃ Photosynthesis in Skin?
The balanced equation is: 7-Dehydrocholesterol → Previtamin D₃ → Vitamin D₃.
What type of reaction is Vitamin D₃ Photosynthesis in Skin?
Vitamin D₃ Photosynthesis in Skin is a photochemical reaction.
Is Vitamin D₃ Photosynthesis in Skin exothermic or endothermic?
Vitamin D₃ Photosynthesis in Skin is endothermic (absorbs energy).