SPECTRA OF PHOTOSYNTHETIC PIGMENTS 357 



Lemberg and Bader, 1933). Two separate phycoerythrins and two 

 phycocyanins are usually recognized (Kylin, 1910; Lemberg and Legge, 

 1949, p. 146), although variations have been found in the reported posi- 

 tions of absorption maxima and their relative heights. R-phycoerythrin, 

 the most common, has three absorption maxima in the visible range, at 

 566, 538, and 497 nin, and C-phycoerythrin has a single maximum at 

 552 m/i. The designation of these two compounds as R- and C-phycoe- 

 rythrin was suggested by Svedberg and Katsurai (1929), since R-phycoe- 

 rythrin is more commonly found in Rhodophyceae and C-phycoerythrin 

 in Cyanophyceae. The absorption curves of these pigments are shown 

 in Fig. 6-6a and c. Higher specific absorption coefficients have been 

 reported by Lemberg (1930a). 



The absorption curves of two other phycoerythrins, presented by 

 Svedberg and Eriksson (1932), are shown in Fig. 6-6a. The maxima in 

 these curves appear to be in the same positions as those for R-phycoe- 

 rythrin, but the relative heights of the three maxima are different. In 

 curve 2 (phycoerythrin extracted from Polysiphonia and Griffifhsia) the 

 maximum at 497 m/x is nearly the same height as that at 565 m/z. In 

 curve 3, for the phycoerythrin extracted from Sebdenia, only a shelf 

 occurred at 538 m;u, and the 497-mpt maximum was much higher than 

 that at 565 m^t. It is evident from these curves that the various phycoe- 

 rythrins differ primarily in the relative proportions of the absorption that 

 is contributed by the three separate bands. No definite difference in the 

 wave length of the fluorescence of these modifications of phycoerythrin 

 has been found (Svedberg and Eriksson, 1932), but the intensity of fluo- 

 rescence of the Polysiphonia and Grijffithsia phycoerythrin (curve 2) was 

 much lower. 



Absorption curves of C-phycoerythrin have been presented by Kylin 

 (1931) and Boresch (1921). Boresch reports a single peak at 552 m^. 

 Kylin's curve shows a secondary maximum at about 496 m/x. The curve 

 presented in Fig. 6-6c is the absorption of the autolysate of Porphyridium 

 cruentwn Naeg (V. K. Young, unpublished data). Whether the C-phyco- 

 erythrin absorption curve actually has shelves at 565 and 496 m/x or 

 whether these shelves are due to the presence of small amounts of 

 R-phycoerythrin in this organism is not known. 



The two phycocyanins that are commonly recognized are R-phyco- 

 cyanin, with two maxima at 614 and 551 m/x, and C-phycocyanin, with 

 one maximum reported at 615 mn by some investigators (Boresch, 1922; 

 Svedberg and Katsurai, 1929; Lemberg, 1930a) and at 625 m/x by others. 

 Lemberg and Legge (1949) suggest that these may be two separate pig- 

 ments. Kylin (1912) has reported another phycocyanin with two max- 

 ima, at 610-615 m/x and 573-577 m/x, respectively, which he obtained 

 from Phormidium, This is shown in Fig. 6-66. 



