268 



Sakae Katoh and Atusi Takamiya 



0.0 



-0.1 



Without oscorbate a DPIP 



'C, 



PC 



PC 



-PC 



-0.6 



-0.7 



Witti ascorbote 

 a DPIP 



\ +PC 

 \ 

 \ 

 \ 

 \ 



_L 



_1_ 



2 3 4 



Time in mm 



Fig. 2. Effect of plastocyanin on the photoreduc- 

 tion of indigo carmine by Brassica Chloroplast 

 with and without ascorbate and DPIP 



TABLE II 



Effect of Plastocyanin on the Photoreduction of Indigo Carmine by 

 Leaf Homogenate, Whole Chloroplasts and Broken Chloroplasts 



Fractions 



umole IC reduced per mg chl. per hr. 

 With ascorbate + DPIP Without ascorbate + DPIP 



- PC + PC - PC + PC 



Leaf homogenate 

 Whole chloroplast 

 Broken chloroplasts 



The data presented in Fig. 3 show that the degree of acceleration induced 

 by the addition of a constant amount of plastocyanin was almost unchanged in 

 the absence or in the presence of widely varied concentration of DPIP. This 

 fact suggests that the role of plastocyanin in the photoreducing system of the 



