34 



CARBON ASSIMILATION 



[CH. 



by means of tlie chlorophyllase, is hydrolyzed into i)hytol and the acid chloi-ophyllide. 

 This can be demonstrated after about a quarter of an hour if the sohition is diluted 

 with water, transferred to ether and shaken with 005 7o sodium hydroxide. The 

 sodium hydroxide takes up more coloui-ing matter the further the enzyme action 

 has progressed. 



Expt. 30. The destruction oj chlorophyllase. If fresh leaves of a species rich in 

 chlorophyllase are first steeped in boiling water for a few minutes before they are 

 placed in the acetone solution, unaltered chlorophyll is extracted which does not 

 react with dilute alkali. 



With acids — > 

 (C,j..,H,3oON4Mg ) (COOCH:,) (COOCmuHs.,) ^ (C,j.H3.0N4) (COOCH:.; (COOCjoHsg) 



chloro2)hyll a pliaeophytin a 



% (C3,H:,oON,Mg) (COOH) (COOH) 

 ^ chlorophyllin a 



^ and isochlorophyllin a 



intermeldiate phyllins 

 \ 



C3iH34N4Mg 



aetiophyllin 



(C3.jH3.ON4) (COOH) (COOH) 



phytochlorin e 

 and phytochlorins / and g 



>■ intermediate porphyrins 



C3iH3gN, 



aetioporphyrin 



Scheme 1. 



chlorophyll a 

 (MgN4C3,>H3„0) (CO6CH3) (COOC.0H30) 



methyl chlorophyllide a 

 (MgN4C3,H3„0) (COOCH3) (COOCH3) 



chloroi)hyllide (( 

 ;MgN4C.,,H3„0) (C00CH3)(C00H) 



with 



dilute acid 



with 



dilute acid 



with 



> 



dilute acid 



Scheme 2. 



phaeophytin a 

 (N4C3.H32O) (COOCH3) (COOC2„H3,,) 



methyl phaeophorbide a 

 .N4C3.,H320) (COOCH3) (COOCH., 





phaeophorbide a 

 [UiC-^M'^.O) (COOCH3) (COOH) 



By treatment with acids, magnesium is removed from the chlorophyl- 

 lides, with the production of the corresponding phaeophorbides. Thus 

 methyl chloi-ophyllide a gives methyl phaeophorbide a, etc. (see 

 Scheme 2. above). 



It has been previously mentioned that water- free solvents, such as 

 acetone, ether and benzene, in which pure extracted chlorophyll is 



