34 



CARBON ASSIMILATION 



[CH. 



by means of the chlorophyllase, is hydrolyzed into phytol and the acid chlorophyllide. 

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

 with water, transferred to ether and shaken with O05 / sodium hydroxide. The 

 sodium hydroxide takes up more colouring 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 32 H 30 ON 4 Mg) (COOCH 3 ) (COOC, H 39 ) - > (C 32 H 32 ON 4 ) (COOCH, 



chlorophyll a phaeophytin a 



(C 32 H 30 ON 4 Mg) (COOH) (COOH) - * (C 32 H 32 ON 4 ) (COOH) (COOH) 



chlorophyllin a phytochlorin e 



and isochlorophyllin a and phytochlorins / and g 



intermediate phyllins 



intermediate porphyrins 



aetiophyllin 



Scheme 1. 



aetioporphyrin 



chlorophyll a 

 -joO) (COOCH 3 



with 



methyl chlorophyllide a ^ 



(MgN 4 C 32 H 30 0) (COOCH 3 ) (COOCH 3 ) 



chlorophyllide a 

 (MgN 4 C 32 H 30 0) (COOCH 3 )(COOH) 



dilute acid 



with 

 dilute acid 



with 



dilute acid 

 Scheme 2. 



phaeophytin a 

 (N 4 C 32 H 32 0) (COOCH 3 ) (COOCaoHs,) 



t>> 

 tg'o 



il 





methyl phaeophorbide a 

 (N 4 C 3 .,H 32 0) (COOCH 3 ) (COOCH 3 ) 



phaeophorbide a 

 (N 4 C 3 .,H 32 O) (COOCH 3 ) (COOH) 



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

 lides, with the production of the corresponding phaeophorbides. Thus 

 methyl chlorophyllide 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 



