513 



Leo P. Vernon, Waldo S. Zaugg and Elwood Shaw 



TABLE 1 



Removal of Chlorophyll from Chloroplasts by Triton X-100 



Chloroplasts equivalent to (a) 135 or (b) 27 ugrams of chlorophyll were ex- 

 tracted for 30 minutes with 10 ml of solution containing detergent at the 

 indicated concentration. The mixture was then centrifuged for 30 minutes 

 at 140, 000 X g in the Spinco ultracentrifuge. The chlorophyll remaining in 

 solution was determined from the absorbancy at 667 mp. 



Per cent Triton X- 100 Per cent Chlorophyll Removed 



a b 



.002 

 .005 

 .010 

 .020 

 .040 

 .080 



the chlorophyll becomes solubilized and the preparation becomes optically 

 clear. The physical properties of such solubilized chlorophyll have not been 

 determined, so it is not known if it exists as free chlorophyll or is attached 

 to a small particle. (Chiba ^^^> has reported the solubilization of a chloro- 

 phyll protein from chloroplasts through the use of Oupanol. ) The absorption 

 spectra of an original chloroplast suspension and the detergent- extracted 

 material were determined with the Cary Model 14 spectrophotometer 

 equipped with an apparatus designed for measuring absorption spectra from 

 highly scattering suspensions. In the red region the absorption maximum of 

 the chloroplast suspension occurred at 676 mp. In the Triton X-100 extract 

 this peak shifted to 667 mp and was sharper and more intense. A sharpening 

 of the absorption bands was also observed in the blue region. This agrees 

 with the data presented by Kondo et al. ^^'*' who examined the effect of 

 various sodium alkyl sulfates upon~the absorption spectra of chloroplasts and 

 derived fractions. 



The rates of PMSH2 photooxidation under the various conditions of deter- 

 gent and acceptor quinone are shown in Table 2. The reactions are shown as 

 either a photooxidation (with ubiquinone and Triton X-100) or a photoreduction 

 (with TMQ regardless of the detergent). The rates are the observed initial 

 reaction rates obtained with the Spectronic 505 spectrophotometer. Since 

 this instrument is limited in its response time, it is probable that the 

 actual reaction rates are faster than those reported in Table 2. 



