686 



William L. Ogren and David W. Krogmann 



Table III 



Inorganic Phosphate, ADP and ATP 

 Distribution in Spinach 



Non Aqueous 

 Whole Leaves Chloroplasts 



mjimoles per (imole chlorophyll 



Inorganic phosphate 



ADP 



ATP 



4.2 X 10' 

 71. 1 

 43.3 



1. 15 X 10" 

 16. 5 

 20.2 



In market spinach, about 20% of the total leaf inorganic phosphate appears 

 in the non aqueous chloroplast fraction. Approximately 23% of the total 

 ADP and 46% of the total ATP are found in these chloroplasts which is 

 reassuring in comparison to the negligible quantities of these nucleotides 

 found in chloroplasts prepared in aqueous media. 



In the hope that leaves freshly picked and immiediately frozen in liquid 

 nitrogen might provide a better representation of the physiological state, 

 red kidney bean plants were used and leaf samples taken from plants held 

 in darkness or exposed to illumination for three hours. The data from a 

 representative experiment are presented in Table IV. 



Table IV 



Effect of Light on Chloroplast 

 Nucleotide Coenzyme Levels 



DPN 

 TPN 



ADP 

 ATP 



Dark Three Hours lUunnination 



7.21 3.38 



3.91 5.58 



23.9 29.5 



12.3 14.9 



m^lmoles per |xmole chlorophyll 



In general, the nucleotide levels of bean leaves are not very different from 

 those found in spinach. However, preillumination causes a distinct shift 

 in chloroplast pyridine nucleotides in that there is a decrease in the DPN 

 and an increase in TPN. A similar shift of DPN to TPN as a result of 

 illumination was observed in whole Chlorella cells by Oh-Hama and 

 Miyachi . Here the shift in form of the coenzyme is seen to occur in the 

 chloroplast fraction and provides some encouragement for the notion that 

 TPN is the preferred coenzyme in biosynthetic or photosynthetic 

 functions. The 20% decrease in total pyridine nucleotide probably reflects 



