1810 



SPECTROSCOPY AND FLUORESCENCE OF PIGMENTS CHAP. 37C 



at 565 mix and a shoulder at 500 m^ also are noticeable. Blinks (1954) 

 suggested (cf. chapter 37B, section 8) that this shows the presence, in 

 Bangiales, of a third type of phycoerythrin ("B-phycoerythrin"); alter- 

 natively, the same chromophore can be associated with different proteins 

 (or other molecules), or present in different forms (as an adsorbed mono- 

 layer, a colloid, or a solution). The situation is quite analogous to that 

 in purple bacteria, where bacteriochlorophyll exhibits, in Thiorhodaceae, 

 three infrared peaks of varying relative intensity and in A thiorhodaceae 

 only one major (and one minor) peak (cf. chapter 22, p. 702). 



toge 

 ''3A 



2.9 



2A 



1.9 





250 300 350 AOO 450 500 550 



m-Xinmfi 



Fig. 37C.1.3. Absorption spectrum of rhodoviolasin (after Karrer and 

 Jucker 1948). e(= 2.30a) = loge (h/I)/cd. 



For phycocyanin, Lemberg and Legge (1949) distinguished two varie- 

 ties — "phycocyanin R" (from Rhodophyceae) , with two absorption bands 

 {e. g., at 614 and 551 m^u), and "phycocyanin C" (from Cyanophyceae) 

 with a single band (e. g., at 615 mju). Blinks (1954) suggested {cf. chapter 

 37B, section 8) that "phycocyanin R" may be a complex of phycocyanin 

 C with phycoerythrin (with the 551 m/x band due to the latter). 



Haxo, O'hEocha and Strout (1954) extracted a new variety of phyco- 

 cyanin from several red and one blue-green alga; it had an absorption 

 peak at 645-650 m/x (halfway between those of phycocyanin C and chloro- 

 phyll). 



A review of the absorption and fluorescence spectra of chlorophyll, 

 carotenoids and phycobilins, with all curves replotted in a unified way, 

 has been prepared by French and Young (1953). 



