from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A protein of the retina, especially the protein constituent of rhodopsin, that makes up one of the visual pigments.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a group of light-sensitive proteins in the retina
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. retinal protein formed by the action of light on rhodopsin
The gene, called opsin, is present in vision among vertebrate animals, and is responsible for a different way of seeing than that of animals like flies.
I had a feeling that my Irish in-laws have a long wavelength opsin and special photoreceptors to allow them to see how hot their tea is.
We vertebrates have ciliary cells, c-opsin, and a phosphodiesterase pathway.
Invertebrates have rhabodomeric cells that use a special version of the photopigment called r-opsin, and activate cells by a particular pathway called a phospholipase-C cascade.
Our complex eyes clearly evolved from the simpler eyes in ancestral species, and the presence of the critical light-receptive pigment called “opsin” in all animals highlights this shared ancestry.
Genetic evidence for selective transport of opsin and arrestin by kinesin-II in mammalian photoreceptors.
Nevertheless in that period, after dissecting retinas from 300 frogs, he found that rhodopsin on stimulation with light yielded both the protein opsin and a compound he called "retinene" (now "retinaldehyde") that in turn yielded vitamin A (now called retinol).
When light strikes the human retina it is absorbed by a molecule [retinal] which alters an attached protein [opsin], which then initiates what biochemists call a “cascade”—a precisely integrated series of molecular reactions that in this case causes a nerve impulse to be transmitted to the brain.
Modern vertebrate cilliary opsin binds to the adaptor protein transducin.
In non-chordate inverebrates, opsin is linked via the adaptor protein to an enzyme called phospholipase C, and in chordates and vertebrates, it is linked to a phosphodiesterase enzyme.
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