Three visual pigments inDeilephila elpenor (Lepidoptera,Sphingidae)

Summary Selective irradiation of digitonin extracts (pH 6.1) from dark-adapted eyes of the Sphingid mothDeihphila elpenor revealed three visual pigments with _max at about 345, 440 and 520 nm. Prom the reaction of the chromophoric group with hydroxylamine it is concluded that these pigments are based on retinaldehyde, and therefore can be classed with rhodopsins. At –15 °C, each of the rhodopsins can completely (P 520) or partially (P 440 and P 345) be converted by light to acid metarhodopsin absorbing maximally at 480 ± 10 nm, which decay at room temperature to retinaldehyde and protein moiety. Spectrophotometric measurements on isolated retinae (pH 7.4) indicate that the metarhodopsins, in contrast to the findings on extracts, are thermostable in the photoreceptor membrane at room temperature. The results are compared with electrophysiological and microspectrophotometrical data. The different properties of the metarhodopsins in detergent solution and in the isolated retina are discussed.This work was supported by grants of the Deutsche Forschungsgemeinschaft to Prof. Dr. K. Hamdori (Rezeptorphysiologie).We would like to thank Miss Gabriele Ziem for excellent technical assistance.