FLA VACIN 



8. FLAVACIN 



307 



^ TisCHER^^ discovered flavacin together with aphanin, aphanicin and 

 aphanizophyll in the blue algae Aphanizomenon flos-aquae. The isolation of the 

 pigment is described in connection with the preparation of aphanin on p. 301. 



TABLE 54 ■. 



COMPARISON OF SOME PROPERTIES OF MUTATOCHROME AND FLAVACIN 



This melting point was not yet constant. 



J. TiscHER employed 30% hydrochloric acid for this reaction, whereas P. Karrer 

 and E. Jucker employed 37% hydrochloric acid but still only observed a very weak blue 

 colouration. 



Chemical Constitution 



Very little is known concerning the structure of flavacin. The pigment is 

 found below aphanin but above /3-carotene in the chromatogram. It has purely 

 epiphasic character which suggests that it may be a hydrocarbon. The ab- 

 sorption maxima in carbon disulphide are located at 490 and 457 m/i, so that 

 the chromophoric system of flavacin must contain fewer conjugated double 

 bonds than, foi instance, that of jS-caiotene. Since, however, the latter is more 

 weakly adsorbed on the chromatographic column, flavacin must contain an 

 additional functional group which increases its strength of adsorption. One is 

 thus tempted to compare flavacin with mutatochrome^^. The two compounds 

 have, in fact, largely the same pioperties. The question of the identity of the two 

 pigments must still be left open, however, as a direct comparison has not yet 

 been made. 



References p. J41—J4J. 



