GG6 



ABSORPTION SPECTRA OF PIGMENTS IN VITRO 



CHAP. 21 



Ceramium 



450 500 550 600 650 450 500 550 600 650 450 500 550 600 650 

 WAVE LENGTH, m/i WAVE LENGTH, m/i WAVE LENGTH, m/i 



Fig. 21.39. Specific absorption spectra of phycoerythrins from different algae 



(after Svedberg and Eriksson 1932). 



80 



60 



» 40 



20 



200 



300 



600 



700 



400 500 



WAVE LENGTH, m/x 

 Fig. 21.40. Specific absorption spectrum of phycocyanin from Aphanizo- 

 menonflos aquae (after Svedberg and Katsurai 1929). 



Figure 21.40 shows the extinction curve of the phycocyanin from Aphan- 

 izomenon flos aquae, according to Svedberg and Katsurai (1929). 



Using Lemberg's estimate of 2% pigment in the chromoproteid (with 

 a molecular weight of 636 for the chromophore, this corresponds to one 

 mole pigment in 3.2 X 10^ g. of the complex) we can convert the specific 

 extinction coefficients, given by Lemberg (1928, 1930) and Svedberg and 

 Katsurai (1929) into molar extinction coefficients. The resulting values 

 (cf. Table 21. X) are exceptionally high — up to 3 X 10^, as against only 4 X 

 lO'* in the maximum of the red band of chlorophyll and 1.5 X 10^ in the 

 maximum of the main absorption band of the carotenoids. This makes the 

 correctness of Lemberg's analytical data somewhat doubtful. Lemberg 



