CARBON DIOXID1-: FIXATION 291 



of phosphorylated sugars and related compounds, as shown in Table 

 III. Figure 1 illustrates schematically the loss of photosynthetic 

 activity of whole chloroplasts by treatment with water and its restora- 

 tion by the various addenda. The level of photosynthetic CO2 fixa- 

 tion by the reconstituted system was several-fold that originally 

 obtained with whole chloroplasts. 



61. 2-64. 

 60m<n. PS 

 P_ .C.E..ATP. TPN 



■y o 



I- 



D -lYC'- 



J# 



MONOPHOSPHATLS 



.GLU'.Oic.rRUCTOSE) 



GLUCOSIDE 

 DIPHOSPHATES 

 (rRUCTOSE.P»lBULOS£) 



I 



P- 



Fig. 2. Chromatogram showing products of photosynthetic CO2 fixation by 

 broken chloroplasts. Compound directly above area labeled "monophosphates" 

 has been identified as phosphoglyceric acid. Experimental procedures as given 



in (2) and (4). 



These experiments with broken chloroplasts were carried out in the 

 presence of ascorbate and manganous ions, which were pre^dously 

 found to stimulate carbon dioxide fixation by whole chloroplasts (2). 

 The omission of Mn++ from the broken chloroplast system reduced 

 CO2 fixation to 20% to 30% of the usual value — a much more marked 

 effect than that previously noted with whole chloroplasts. 



