588 VI. CAROTENOIDS AND RELATED COMPOUNDS 



and also the swimming crab {Portunus puber-) ,*^^'^^^ and crayfish {Nephrops 

 spp.)-^^° Astacene has also been demonstrated in salmon oil and 

 muscle,^^^'"*^^ as well as in the eggs of the cod.^^^ It occurs in the copepods 

 {Calanus finmarchicus) of the plankton, ^^* in the red shrimp {Palaemonetes 

 vulgaris), "^^^ and in the red sponge (Axinella crista-galli) ^^^ Karrer and 

 Solmssen'"'^ also suggested that astacene miglit be present in the clavuline 

 sponge {Snberifes domuncula), although this is at variance with the results 

 of Lederer.^^* The presence of astacene in the liver oil and feces of the 

 whale is attributed to the fact that this mammal consumes large amounts of 

 the pigment in the "krill," which consists largely of small crustaceans/^'^-'''* 

 In addition, astacene has been recognized in several terrestrial animals. 

 Its presence in the cones of the retina of the chicken, pigeon, and turtle, 

 along with xanthophyll esters, represents a most unexpected source.*'^ It 

 is believed to function in some way to render color vision possible. An 

 astacin-like compound has been separated from a red yeast (Torula rubra) 

 by Lederer.^^" It was accompanied by j8-carotene and by "torulene." 



(2) Astaxantkin 



Although astaxanthin was first studied by Newbigin^'-' in 1897, it was 

 not until the investigations of Kuhn and S0rensen*--'^"^ that its relationship 

 to astacene became apparent. The latter workers proved that the pig- 

 ment in the eggs of the lobster was not esterified astacene ("ovoester"), but 

 rather a new pigment which was called astaxanthin. They indicated its 

 constitution and demonstrated its close relationship to astacene. 



The pigment apparently occurs as the prosthetic group of a conjugate 

 protein,^* in which the carrier protein is an albumin. Stern and Salo- 

 mon^-^'^-^ have reported that the protein complex of astaxanthin, obtained 



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"0 R. Fabre and E. Lederer, Bidl. soc. chim. hiol, 16, 105-117 (1934). 



"1 N. A. S0rensen, Z. physiol. Chem., 235, 8-11 (1935). 



■•^^ A. Emmerie, M. van Eekelen, B. Josephy, and L. K. Wolff, Acta Brevia Neerland. 

 Phij&iol. Pharmacol. Microbiol, 4, 139-141 (1934). 



^1' A. Emmerie, M. van Eekelen, and L. K. Wolff, Acta Brevia Neerland. Physiol 

 Pharmacol Microbiol, 4, 5-6 (1934). 



41* H. V. Euler, H. Hellstrom, and E. Kluasmann, Z. physiol Chem., 228, 77-89 (1934). 



"« F. A. Brown, Biol Bull, 67, 365-380 (1934). 



416 p. Karrer and U. Solmssen, Helv. Chim. Acta, 18, 915-921 (1935). 



4" J. C. Drummond and R. J. Mac Walter, /. Exp. Biol, 12, 105-107 (1935). 



41* S. Schmidt-Nielsen, N. A. S0rensen, and B. Trumpy, Kgl. Norske Videnskah. Sels- 

 kab. Forh., 5, No. 30, 118-121 (1932). 



419 G. Wald and H. Zussman, Nature, I40, 197 (1937). 



420 E. Lederer, CmnpL rend., 197, 1694-1695 (1933). 



421 M. I. Newbigin, J. Physiol, 21, 237-257 (1897). 



422 R. Kuhn and N. A. S0rensen, Ber., 71, 1879-1888 (1938). 



423 R. Kuhn and N. A. S0rensen, Z. angew. Chem., 61, 465-466 (1938); Chem. Ahsl, 32, 

 7138(1938). 



424 K. G. Stern and K. Salomon, /. Biol Chem., 122, 461-475 (1938). 

 426 K. G. Stern and K. Salomon, Science, 86, 310-311 (1937). 



