THE NATURAL STATE OF PROTOCHLOROPHYLL 



469 



appear even to contain an inhibitor for the transformation, inasmuch 

 as an extract of a mixture of barley and bean leaves caused a lessening 

 of the transformation of bean-leaf protochlorophyll holochrome 

 (Fig. 3). 



Our experiments on the partial isolation of the active protochloro- 

 phyll holochrome will now be described. From 8 to 10 g. of etiolated 



ABSORPTION SPECTRA 



f ' ' ' 



lResusp«iided Sedimegt 



600 700 SOO 



WAVEIENGTH 



too 



700 800 



too 



700 800 



SEDIMENTATION PATTERN 

 In Sfiillietu loaidorr Cell ot 50,740 R.P.M. 



X 



K 



10 Min. 



9 Min. 



9 Min. 



Fig. 4. The photochemical properties and sedimentation patterns of a glj'cine 

 buffer extract of etiolated bean leaves: A, D before being centrifiiged at higli speed, 

 B, E the supernatant, and C, F the sediment after 3 hours centrifugation at 40,000 

 r.p.m. The sediment had been resuspended in fresh buffer. Glycine buffer: 0.1 3/ 

 glycine, 0.05 potassium hydroxide; pH, 9.5. In A, B, and C the full line refers to 

 the unilluminated solutions and the broken line to the illuminated solutions. In 

 the sedimentation patterns, sedimentation proceeds from left to right. 



bean leaves were harvested about two weeks after planting and were 

 ground for 15 minutes in 30 ml. of glycine buffer, pH 9.5, containing 

 0.1 molar glycine and 0.05 molar potassium hydroxide. Glycine 

 buffer was used because the extracts were more stable in this medium 

 than in phosphate buffer. The extract was squeezed through a fine- 

 woven cloth, centrifuged for 10 minutes at 10,000 X g to remove 



