op·​sin | \ ˈäp-sən How to pronounce opsin (audio) \

Definition of opsin

: any of various colorless proteins that in combination with retinal or a related prosthetic group form a visual pigment (such as rhodopsin) in a reaction reversible by light

Examples of opsin in a Sentence

Recent Examples on the Web Within 6 months, the ganglion cells in the patient’s eye had begun making the opsin protein. Caroline Seydel, Forbes, 14 June 2021 To do this, the researchers injected a gene for an opsin directly into the eye. Caroline Seydel, Forbes, 14 June 2021 That means the patients could potentially gain vision by giving these cells a microbial opsin. Jocelyn Kaiser, Science | AAAS, 24 May 2021 Setups sometimes use cameras and special goggles to project light wavelengths and intensity optimized for the opsin being used, but scientists are also testing opsins that respond to direct light. Simon Makin, Scientific American, 23 Apr. 2021 Depending on the opsin, researchers can excite or inhibit neurons by shining light on them, usually via an implanted optical fiber. Kelly Servick, Science | AAAS, 28 Oct. 2020 But for now, getting an opsin into monkey neurons means infecting the cells with a virus injected through a hole in the skull. Kelly Servick, Science | AAAS, 28 Oct. 2020 Researchers still need to demonstrate that a virus can safely and reliably endow particular neurons with an opsin gene that sticks around for years. Kelly Servick, Science | AAAS, 31 Oct. 2019 To better understand the mechanics behind the species’ chameleon-esque appearance, Eacock, then a graduate student in Saccheri’s lab, tested caterpillars’ eyes and skin for light-sensitive proteins known as opsins. Meilan Solly, Smithsonian, 27 Aug. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'opsin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of opsin

1951, in the meaning defined above

History and Etymology for opsin

from -opsin (in porphyropsin and rhodopsin)

Note: Term introduced by the American physiologist George Wald (1906-97) in "The Chemistry of Rod Vision," Science, vol. 113, issue 2933, March 16, 1951, p. 287: "Rhodopsin and porphyropsin are carotenoid-proteins—proteins bearing carotenoid prosthetic groups to which they owe their color and sensitivity to light. Each of these pigments possesses a single type of prosthetic group. The protein probably varies from one animal to another; it may be called opsin, and named for the animal of origin."

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Cite this Entry

“Opsin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/opsin. Accessed 17 Jan. 2022.

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More Definitions for opsin


op·​sin | \ ˈäp-sən How to pronounce opsin (audio) \

Medical Definition of opsin

: any of various colorless proteins that in combination with retinal or a related prosthetic group form a visual pigment (as rhodopsin) in a reaction which is reversed by light

More from Merriam-Webster on opsin

Britannica.com: Encyclopedia article about opsin


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