alltransretineal

All-transretinal, also known as retinal or retinaldehyde, is a crucial molecule in the visual process. It is an aldehyde form of vitamin A, and it is the light-sensitive chromophore found in the protein opsin, which together form rhodopsin. Rhodopsin is the primary photopigment in rod cells of the retina, responsible for vision in low light conditions.

When light strikes rhodopsin, all-transretinal undergoes a rapid isomerization from its original 11-cis form to its all-trans form. This structural change triggers a cascade of events within the rod cell, ultimately leading to a nerve impulse that is transmitted to the brain and interpreted as vision. Following this phototransduction, all-transretinal is released from opsin and must be converted back to the 11-cis form to regenerate functional rhodopsin. This process involves a series of enzymatic reactions occurring in the retinal pigment epithelium and photoreceptor cells, collectively known as the visual cycle.

Deficiencies in vitamin A, which is the precursor to retinal, can lead to impaired vision, particularly night blindness, due to insufficient production of functional rhodopsin. All-transretinal itself plays a pivotal role in the absorption of light photons and the initiation of the visual signal. Its transformation is a fundamental step in how we perceive the world around us.