Definition of opsin in English:

opsin

noun

mass nounBiochemistry
  • A protein which forms part of the visual pigment rhodopsin and is released by the action of light.

    • ‘The transport of opsin to the outer segment of photoreceptor cells seems especially critical for viability of these cells.’
    • ‘Visual pigments are composed of a light-absorbing chromophore that is bound to the protein opsin.’
    • ‘Every photopigment consists of a derivative of vitamin A linked to a protein molecule called an opsin.’
    • ‘Rhodopsin consists of a protein called opsin bonded to a pigment called retinal.’
    • ‘Vitamin A then combines with a protein opsin to form rhodopsin.’

Origin

1950s: shortening of rhodopsin.

Pronunciation

opsin

/ˈɒpsɪn/