11cisretinoic

11-cisretinoic acid, also known as 11-cis-retinal, is a visually active molecule. It is a stereoisomer of retinal, a form of vitamin A. 11-cisretinoic acid is a crucial component in the process of vision in vertebrates.

In the retina, 11-cisretinoic acid is bound to a protein called opsin, forming the light-sensitive pigment rhodopsin. When a photon of light strikes rhodopsin, it causes a conformational change in the 11-cisretinoic acid molecule, isomerizing it to all-transretinoic acid. This isomerization triggers a signal transduction cascade that ultimately leads to a nerve impulse being sent to the brain, which is perceived as vision.

The cycle of light absorption and isomerization is known as the visual cycle. Following its isomerization, all-transretinoic acid is released from opsin and must be converted back to its 11-cis form to regenerate rhodopsin and allow for further light detection. This regeneration process is essential for maintaining visual function.

While its primary role is in vision, retinoids, including derivatives of retinoic acid, also play important roles in cellular differentiation, growth, and development. However, 11-cisretinoic acid's direct involvement is most prominently recognized within the photoreceptor cells of the eye.