232 PIGMENTS 



Phfise Test. Phase Test. Phase Test. 



(i.e. hydrolysis in ethereal Transient pure yellow Transient brilliant red 

 solution, with methyl colour. colour. 



alcoholic potash), gives 

 a transient brown 

 coloration (cf. p. 238). 



From the above data it will be seen that neither ordinary 

 chlorophyll (a and ) nor either of the constituents of this 

 mixture show any marked tendency to crystallize which at 

 first sight would appear to be in contradiction with the well- 

 known fact first observed by Borodin * that when -green leaves 

 are moistened with alcohol, and allowed to evaporate slowly 

 under a coverslip, crystals of chlorophyll may be observed 

 under the microscope. Willstatter and Benzf described a 

 method of obtaining this substance in quantity from Galeopsis 

 tetrahit, and later Willstatter and StollJ showed that this 

 so-called crystalline chlorophyll was not present as such in the 

 plant, but was a secondary product produced by the action 

 of the alcohol upon the chlorophyll under the action of 

 an enzyme chlorophyllase. The phytyl group is thereby re- 

 placed by the ethyl group as illustrated by the equation : 



/COOCHg /COOCHg 



, + C 2 H 5 OH = C 31 H 29 N 3 Mg^COOC 2 H 5 + 



NH NH 



Amorphous Chlorophyll a Crystalline Chlorophyll a 



For the monomethyl ester of chlorophyllin a Willstatter has 

 proposed the name chlorophyllide a, 



/COOCH 3 

 / 



NH 



and adopting this nomenclature, amorphous chlorophyll would 

 be termed! phytylchlorophyllide, while crystalline chlorophyll 

 would be ethylchlorophyllide. 



Chlorophyllase belongs to the same class of enzymes as 

 lipase ; the latter substance, however, is only able to hydrolyse 

 amorphous chlorophyll, replacing the phytoxyl group by 

 hydroxyl ; it cannot effect alcoholysis, 



* Borodin : " Bot. Ztg.," 1882, 40, 608. 



f Willstatter and Benz : " Annalen," 1907, 358, 267. 



I Willstatter and Stoll : id., lyio, 378, 18. 



