499 



Joseph S. Kahn 



foot-candle was too low to be reliably measured by our assay 

 method. 



30h 



>- 



>20 



o 

 < 



o 



o 

 Ijj 



CL 

 CO 



10 



/ 



./ 



10 10 



FOOT- CANDLE 



10' 



Figure I. The rate of ferricyanide reduction by the 

 protein-chlorophyll as a function of light intensity. 



A Water Soluble Protein-Carotene Complex 



While attempting to separate the protein-chlorophyll into the 

 protein and chlorophyll moieties, we succeeded in isolating a 

 second protein-pigment complex from the protein-chlorophyll (6). 



Samples of the protein-chlorophyll were extracted 5 times 

 with equal volumes of 25% diethyl ether in petroleum ether. 

 The pooled solvent was washed twice with water, dried, dissolved 

 in 0.002 M Tris buffer, pH 8.0 and cleared by centrifugation. 

 The resultant yellow solution was slightly opalescent. 



The absorption spectra of the extracted protein-chlorophyll 

 and of the extract in buffer are given in Figure II. The 

 absorption maxima of the extract in different solvents are pre- 

 sented in Table III. No quinone derivatives reducible with 



