532 



John A. Bergeron 



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10- 

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-1 — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — 1 — I — I — 1 — r 

 ABSORPTION OF PURE PHYCOCYANIN 

 IN OIM PHOSPHATE BUFFER 

 NORMALIZED TO EQUAL PROTEIN 

 CONCENTRATIONS 



pH 5.7 



pH 6 3 



pH 7 5 — • — 



HALF-BAND WIDTH 



pH 5 7 64 m^ 

 pH 6 3 68m;i 

 pH 7 5 75 m^ 



260 300 360 420 480 540 600 660 720 760 



WAVE LENGTH m^ 



Fig. U. Effect of pH on the absorption of piirified 

 phycocyanin. 



MII|IIII{llll{llll{llll|ll ll{ llll|llll| llll|lll l|llll| |[M{I II l|llll| llllj llll|llll|lllk 



PHYCOCYANIN 



MONOMER 



DIMER 



V AGGREGATE 



ri 1 1 1 tn 14-kTnl 1 1 1 1 1 II 1 1 1 1 1 1 1 1 N 1 1 1 1 111 1 1 1 1 1 1 1 1 1 1 1 1 ] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 i I I 1 1 1 J 1 1 1 17 



620 640 660 680 700 720 740 760 



Fig, 5» Fluorescence of pure iihycocyanin in several 

 states excited at 578 d^* 



phycocyanin can exhibit a fluorescence maximum very close to the 

 fluorescence of chlorophyll in vivo . 



V/hen Anacystis is extracted repeatedly with 80^ acetone and 

 returned to buffer, the fluorescence excited at 578 in^ or hsS mn 



