CAROTENOIDS 



This has been confinned by Karrer and Sohnssen* and by Heilbron, 

 Jackson and Jones ; * * the latter isolated, by careful hydrolysis of actin- 

 oerythrin, the parent acidic carotenoid which they named violerythrin ; 

 a rather striking feature of this carotenoid, of which the structure is 

 still unknown, is the considerable difference between its absorption 

 spectrum and that of its ester (Table 24) for esterification of carotenoids 

 does not normally alter the spectra of the parent compounds to any 

 appreciable extent. Heilbron et al. also isolated a second ester, very 

 probably a taraxanthin ester. 



In the green variant Fabre and Lederer foiind the pigment identified 

 by Heilbron as a taraxanthin ester ; as noted with actinioerytnin, this 

 pigment was bound to a protein, which, in this case, assumes a green 

 colour. The brown variety appears to be intermediate between the 

 green and red, containing both actinioerythrin and a taraxanthin ester. 



Table 24. — Characteristic Coelenterate Carotenoids 



REFERENCES TO TABLE 24 



Fabre, R., and Lederer, E. (1934). Bull. Soc. Chim. Wo/., 16, 105. 

 Heilbron, L M., Jackson, H„ and Jo^fES, R. N. (1935), Biochem. J., 29, 1384. 

 Fox, D. L., and Pantin, C. F. A. (1941), PM. Trans. Roy. Soc, 230B, 415. 



* Apparently a very wide absorption band. 



Other coelenterata also contain specific xanthophylls. Sulcatoxan- 

 thin (C40H62O8) a xanthophyll of unknown composition (see Table 24) 

 was isolated from Anemonia sulcata^ ^ and is probably identical with 

 peridinin (see p. 134) ; a very similar, if not identical, carotenoid was 

 detected in Cribrina xanthogrammica^^ and Metridium senile (Actino- 

 loba dianthus). ^ ^ The pigments in the former are due to the presence 



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