1914] Clarence J. West 237 



At higher temperatures the alkaH causes decompositions, with 

 the elimination of carbon dioxide and the formation of the phyl- 

 lines and porphyrines. 



Gentle treatment with acids first causes a displacement of the 

 magnesium by two atoms of hydrogen, f orming pheophytine ; more 

 vigorous treatment saponifies the phytyl group with the formation 

 of pheophorbide : 



Chlorophyllase.^^ The second objection to the earher methods 

 of extraction was the action of the enzyme. It was found early in 

 the work on chlorophylP^ that the preparations varied greatly in 

 their phytol content, especially if the extract was allowed to stand 

 in contact with the leaf meal for any length of tinie. At first this 

 was thought to be due to differences in the Chlorophylls of dififerent 

 plants, but later it was found that the green plant contained an 

 enzyme which had the property of Splitting phytol from Chlorophyll. 

 This enzyme has been called chlorophyllase. It is especially stable, 

 as its use in conc. alcohol and acetone sol. shows, even withstand- 

 ing short heating in alcoholic sol. It is destroyed by treating the 

 leaves with boiling water. It is insoluble in organic solvents, as 

 the extracts, after being filtered from the leaf meal, are not further 

 changed. Chlorophyllase has been found in all the classes of plants 

 investigated, though only in a f ew in sufficient quantity for prepara- 

 tive purposes : hemp nettle, hogweed and hedge nettle. 



Chlorophyllase is used in the form of the dry leaf meal, ground, 

 and usually extracted with alcohol to remove most of the Chlorophyll. 

 The strength of the enzyme is measured as follows : If one kilo of 

 dry leaf meal yields an extract of 3 gm. of Chlorophyll and contains 



^6 Willstätter and Stoll: Ann. d. Chem., 378, 18 (1910) ; 3S0, 154 (1911) ; 

 387, 317 (1911)- 



" Willstätter and Oppe : Ibid., 378, 4 (iQiO- 



