TIME (Minutes) 

 Fig. 2. Effect of successive periods of illumination and darkness on ATP levels 

 in mixtures of firefly enzyme and chloroplasts. Reaction mixture contained: 

 0.2 ml firefly enzyme 



1.4 ml suspension medium containing, per ml the following: 

 1.6 ^mole K0HPO4 

 17.0 /^moles NaCl 

 3.38 yumoles MgCU 

 19.0 MHioles tris-HCl 

 buffer pH 8 

 0.1 ml PMS (5 X 10-^ M solution) 

 0.1 ml AMP (2 X 10 = M solution) 



0.2 ml Chloroplast suspension (about 700 mg chlorophyll /ml suspension) 

 All reagents taken to pH 7.5-8.0 before adding to mixture; light intensity approxi- 

 mately 3.50 ft-candles. L, light; D, dark. 



iij 

 o 



z 



LiJ 

 O 

 W 

 111 



< 

 _J 

 UJ 



TIME (Minutes) 

 Fig. 3. Time course of luminescence dining first illumination 

 period, without addition of .\ IP or A DP. 

 Sensitivity changed at arrow. 

 Reaction mixture, same as in Fig. 2, except that 0.1 ml firefly enzyme was used. 



