metarhodopsinn.
/ˌmɛtərə(ʊ)ˈdɒpsɪn/, U.S. /ˈˌmɛdəˌroʊˈdɑps(ə)n/ Biochemistry and Physiology.
Any of three intermediates formed during the photolysis of the visual pigment rhodopsin. metarhodopsin I n. a compound with peak absorbance at 478 nanometres, formed from lumirhodopsin and deprotonated to form metarhodopsin II. metarhodopsin II n. a compound with peak absorbance at 380 nanometres, formed from metarhodopsin I and hydrolysed to (all-trans-)retinal and opsin directly and through conversion to metarhodopsin III. metarhodopsin III n. a compound with peak absorbance at 465 nanometres, formed from metarhodopsin II and decaying to (all-trans-)retinal and opsin.
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the world > life > biology > substance > pigment > [noun] > human or animal pigments > purple > rhodopsin
rhodophane1878
rhodopsin1878
visual purple1878
lumirhodopsin1950
metarhodopsin1950
prelumirhodopsin1963
1950 G. Wald et al. in Science 17 Feb. 180/1 If the solution of lumi-rhodopsin is warmed to about −20°C, a further change occurs in darkness. The absorption band shifts another 7–9 mμ toward the blue, with little further change in height or shape... We shall call this second product meta-rhodopsin.
1970 G. S. Brindley Physiol. Retina (ed. 2) i. 11 Figure 1.4 shows the effect of pH on the absorption spectrum of metarhodopsin at 3·2°C. Increase of temperature favours the acid form (‘metarhodopsin II’).
1970 G. S. Brindley Physiol. Retina (ed. 2) i. 11 It seems that when rhodopsin is bleached by light the alkaline form (‘metarhodopsin I’) is always formed first, and this passes quickly into the equilibrium mixture appropriate to the pH and temperature.
1972 Jrnl. Physiol. 222 647 Metarhodopsin III is also termed pararhodopsin or 465 nm compound.
1975 Nature 3 Jan. 56/2 Lozier and Stoeckenius have observed [in Halobacterium halobium] four spectrally distinct intermediates analogous to the rhodopsin, prelumirhodopsin, lumirhodopsin and metarhodopsin of invertebrates.
1985 Exper. Eye Res. 40 531 The eye cup of the skate..was employed..to follow the changes of these two metarhodopsins.
1993 Jrnl. Biol. Chem. 268 9400 Upon illumination, each pigment was converted to a metarhodopsin II-like spectral form (λ-max = 380 nm).
1997 W. C. Gordon & N. G. Bazan in J. J. Harding Biochem. Eye vi. 184/1 Meta II then decays to metarhodopsin III (meta III) with the release of all-trans-retinal.
This entry has been updated (OED Third Edition, December 2001; most recently modified version published online March 2022).
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n.1950