230 PIGMENTS 



Thus amorphous chlorophyll is the methyl phytyl ester of 

 this acid, and lias the formula — 



^COOH 

 C3,H2j,N,Mg— COOCH3 



\cOOCo0H3a 



while crystalline chlorophyll is the methyl ethyl ester of the 

 formula — 



yCOOH 

 C,iH,,N,Mg-COOCH3 

 \COOC0H5 



The monomethyl ester of this same acid chlorophyllin 

 having the formula — 



/COOH 

 CsiH^yN^Mg— COOH 



\cOOCH3 



is known as chlorophyllide, and for this reason Willstatter 

 proposes the name phytylchlorophyllide for amorphous chloro- 

 phyll and ethylchlorophyllide for the crystalline compound 

 first described by Borodin. 



That phytylchlorophyllide (amorphous chlorophyll) loses its 

 phytyl radicle under the influence of the enzyme chlorophyllase 

 was shown by Willstatter and Stoll,* who observed that in 

 the presence of alcohol the ester undergoes alcoholysis, setting 

 free one molecular proportion of phytol and replacing it in 

 the molecule by an ethyl group with the formation of ethyl 

 chlorophyllide, or crystalline chlorophyll, according to the 

 equation — 



yCOOH /COOH 



CgiH^yN^Mg— COOCH3 + C,H,OH = C^iHoyN.Mg— COOCH3 + a^HyyOH 



\COOC20H39 Xcooc^Hj 



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. 



On the other hand, working with methyl alcohol and 

 chlorophyllase, it has been found possible to replace the phytyl 

 group by methyl, forming methylchlorophyllide, which is the 



* Willstatter and Stoll : " Annalen," 1910, 378, 18. 



