582 



Jeraiie J. WoUcen 



ctLloroplastin shows sinillarlties to the absoirption spectrum of a 

 chloroplast. Hovrever, chloroplastin is a very canplex system of 

 chlorophyll, carotenoicl, c;)'tochrarae, phospholipid, lipids, and 

 protein (Table II). 



TABTJC II 

 Chloroplastin 



w, dry weight mg/ml 27.3 



n, nitrogen mg/ral 0,36 _ 



p, chlorophyll moles /ml 6.3 x 10"^ 



c, Gytochrome-552 raoles/ral 1.8 x 10" ' 



Rob included in this analysis are the carotenoids vhich are also 

 extracted. 



Chloroplastin, not fixed or stained, and vlevred directly in 

 the electron microscope (Fig. 0) reveals particles (<100-1000S) of 

 the same order as observed by electron microscopy in the fixed 

 chloroplast sections (Fig, 7). If each chloroiDlastin micelle is 

 estiirated to be about 200 R in diameter, it vould have 225 chloro- 

 phyll molecules, 55 carotenoid molecules, and one cytochrome mole- 

 cule vith its protein and lipids, and its molecular weight would 

 be of the order of a ral3J-ion . This is in agreement with the 

 "chlorophyll holochrome" of Smith'-^^Jand close to the minimum 

 size for the active photos;;,Tathetic unit as postulated by Emerson 

 and Arnold '^20)^ 



PITCTOCPHvlICAL ACTIVITY 



Chloroplastin exhibits photochemical activity In solution, The 

 photore duct ion of the dye 2,6, dichlorobenzenoneindophenol at 6OO 

 mii exhibits a primary lohotocheriiical reaction, for during photo- 

 sioithesis, -vTater-siDlitting reduction provides the chemical reduc- 

 ing pa/er which is trapped by the dye, and consequently the dye is 

 reduced to a colorless forra, Chloroplastin extracts that sho\TOd 

 active dye reduction irere observed to liave an absorption peak at 

 ^-88 mii. (one of the Euglena carotenoids) which increased in the 

 llglit and then decreased in the dark withoiit fiarfcher addition of 

 dye.i-'-) This has analogies to .the bleaching and regeneration of 

 the visual complex, rhodopsin^-'-^^. 



Chloroplast ins which actively photoreduced dye were also test- 

 ed for their ability to c8,u.se lohotolysis or evolution of oxygen. 

 Photolysis \-/as measured rnanometrlcally in completely anaerobic 

 Warburg Vessels, niade oxygen-free to permit a CLualitative identi- 

 fication of oxygen with yields of 20 to 30 \jlL of Og in two min- 

 utes. This also sheared a distinct luminescent glo\7 persisting 



I 



