Product name :Nutrition enhancers, food additives, VA
Molecular weight :286.45
Appearance :Pale yellow crystalline powder
shipping :by sea or air
Usages:Involved in maintaining the dark vision photoreceptor cycle in the visual cells
One of the classic, or earliest known, functions of vitamin A is its role in maintaining the dark photoreceptor cycle in the visual cells. Rods in the retina contain rhodopsin, which is made by combining 11- cis - retinal with opsin and is sensitive to dark light. After being sensitized by retinoids, 11-cis retinoids are converted to all-trans retinoids and separated from retinoids to generate visual electrical signals. The dissociated all-trans retinol is reduced to all-trans retinol in rod cells and transported to retinal pigment epithelial cells. Together with the all-trans retinol from plasma, the complex isomerization process is initiated to participate in the supply of 11-cis retinal needed to resynthesize retinoids and maintain dark light adaptation. Thus, to maintain good dark vision, a constant supply of 11- cis - retinaldehyde is needed for rod cells. When vitamin A is deficient, the supply of 11- cis retinaldehyde decreases and the dark adaptation time is prolonged.