Illustrated Glossary of Organic Chemistry

Rhodopsin (visual purple): The retina protein that harvests visible light photons, a process necessary for vision.

	+		Enzyme
Opsin		Retinal		Rhodopsin

Rhodopsin is formed by combination of the primary amine group in the side chain of a lysine residue in opsin (a protein; shown in red) with the carbonyl group of retinal (a conjugated aldehyde; shown in blue).