Abstract
Vertebrate photoreceptor cells, rods and cones, are responsible for scotopic and photopic vision, respectively. Based on their spectral sensitivities, cones can be further classified into several types having different visual pigments. This is the origin of color vision. As compared with a vast amount of work on the visual transduction process in rods, little is known about this process in cones. I have investigated characteristic properties of chicken cone visual pigments to elucidate eventually the molecular basis of color vision. Recent studies on iodopsin, a chicken red-sensitive cone pigment, including its primary structure and functions (photoreactions and interaction with a G-protein) are summarized in this article.
