porphyropsin
/ˌpɔːfɪˈrɒpsɪn/Biochemistry
noun
Any of a class of light-sensitive pigments found in the retinas of freshwater vertebrates, analogous to rhodopsin in humans but differing from it in containing the aldehyde of vitamin A 2 rather than that of A1 and in having a maximum absorption of visible light at a slightly longer wavelength.
Origin
1930s. From porphyro- + -opsin. Compare later opsin.