Photoreceptor Pigments

Kakitani, H. Kakitani, and S. Yomosa, Biophys. Struct. Mech., 1980, 7, 101. 

Fransen, I. Palings, and J. Lugtenburg, Reel. Trav. Chim. Pays-Bas, 1980, 99, 384. 

Biosynthesis and Metabolism.—Biosynthesis. Carotenoid biosynthesis is dealt with extensively in the book by Goodwin1 and the chapter by Spurgeon and Porter,2 

Towner, W. Gaertner, B. Walckhoff, D. Oesterhelt, and H. Hopf, FEBS Lett., 1980, 117, 367. 

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Doughty MJ, Diehn B (1980) Flavins as Photoreceptor Pigments for Behavioral Responses. 41 45-70... 

Song PS and Moore TA. 1974. On the photoreceptor pigment for phototropism and phototaxis Is a carotenoid the most likely candidate Photochemistry and Photobiology 19 435 441. 

Therefore, the action spectrum for phototropism does not simply reflect the absorption spectrum of the active photoreceptor pigment itself, but instead, its absorption spectrum somehow modified by shading pigments. However, on this basis Thimann and Curry failed to calculate a curve fitting the experimental action spec-... 

Of the protozoa in which flavins have been proposed to serve as photoreceptor pigments for behavioral responses, Euglena has been the most intensely studied. In this contribution a survey is given of the historical studies of photomovement in this organism, followed by a critical discussion of the experimental conditions under which such studies might be carried out. 

Different photoreceptor pigments may reasonably be expected to undergo different primary photoprocesses upon light absorption, aside from possessing different spectral characteristics. Specifically, light absorption in flavins fairly easily leads to electronic excitation of the molecule to the triplet state, while this process does not readily occur in carotenoids87). 

The molecular basis of most of these processes is not yet clear. Most of what we know concerns the absorption of quanta by the photoreceptor pigments, while stimulus transformation and signal transmission have as yet been investigated only in part and in a very few organisms. In blue-green algae, not even the movement mechanism is clear, so that any model of the motor response is highly speculative. 

Bok, D. Retinal photoreceptor-pigment epithelium interactions. Invest. Ophthalmol. Vis. Sci. 26 1659-1694,1985. 

Shand J, Foster RG 1999 The extraretinal photoreceptors of non-mammaKan vertebrates. In Archer SN, Djamgoz MBA, Loew ER, Partridge JC, Vallerga S (eds) Adaptive mechanisms in the ecology of vision. Kluwer Academic Publishers, Dordrecht, Netherlands, p 197—222 Smyth RD, Saranak J, Foster KW 1988 Algal visual systems and their photoreceptor pigments. Prog Phycol Res 6 255-286... 

DobidS, B. Surfactant Adsorption on Minerals Related to Rotation. Vol. 56, pp. 91-147. Doughty, M. J., Diehn, B. Flavins as Photoreceptor Pigments for Behavioral Responses. Vol. 41, pp. 45-70. 

Fast excited-state reaction in the photoreceptor pigment-protein complex of the ciliate Blepharisma japonicum... 

Photoreceptor Pigments. There have been several reviews on the structures, photochemistry, and functioning of the retinal-protein photoreceptor pigments involved in the processes of visionand in the purple membrane of Halobacteria (bacteriorhodopsin). ° ° In addition to the papers quoted earlier on the spectroscopy of these pigments, many other reports have appeareddealing with rhodopsin and intermediates in its photocycle, especially photochemistry, chromophore-protein conformation and binding, and reaction kinetics. Similar studies on bacteriorhodopsin have also been described." "-"" ... 

Degraded Carotenoids Physical Methods Separation and Assay N.M.R. Spectroscopy Mass Spectrometry Chiroptical Methods Electronic Absorption Spectroscopy Infrared and Resonance Raman Spectroscopy Other Spectroscopic Techniques Miscellaneous Physical Chemistry Photoreceptor Pigments Biosynthesis and Metabolism Stereochemistry Enzyme Systems Inhibition and Regulation... 

Fig. 3. Examples of natural photoantenna chromophores (2) 5,10-methenyltetrahydrofolate (MTHF), a blue light photoreceptor pigment present in photolyase and some cryptochromes (3) Pheophytin a, the primary electron acceptor in cyanobacterial oxygenic photosynthesis. (4) 11-cis-retinal, which is involved as sensory photoreceptor component in the opsin-based visual process of animals and (5) the p-hydroxy-benzylidene-imidazolinone chromophore (HBDI) of the green fluorescent protein from bioluminescent marine species.

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