1914] Clarence J. West 239 



Double amounts of enzyme produced the same effect in five 

 hours that half that amount produced in ten hours. Thus the 

 action f ollowed Schütz's law : u = k VEt. This law also held f or 

 values in the ratio of 1:2:4. Decreasing the concentration of the 

 Chlorophyll sol. decreased the value of k. 



The presence of water is favorable to the reaction; 92 percent 

 alcohol gave a value of 57.4 for k, while under the same conditions 

 80 percent alcohol gave a value of 140.3. Calcium carbonate is 

 without effect upon the enzyme ; magnesium oxide retards its action 

 very markedly. 



The Optimum temperature for the action of chlorophyllase is 

 20°, the value for u after five hours being 33.3; at 25°, u is 25.3; 

 at 35°, 21.9. Heated two days at 50° the meal was nearly enzyme- 

 free. Treated for forty minutes with boiling 96 percent alcohol, 

 the enzyme still retained about 0.2 of its original power. 



Some of the enzyme may be pressed out with the juice of the 

 leaf, though the press cake is more active than the extract. The 

 enzyme in the juice may be precipitated by adding two vol. of ab- 

 solute alcohol. 



The following reactions may be carried out by the use of chlo- 

 rophyllase : 



Chlorophyllase, acting upon an ethyl alcohol sol. of Chlorophyll, 

 saponifies off the phytyl group and esterifies the free carboxyl group 

 thus formed with ethyl alcohol. This gives ethyl chlorophyllide, 

 which is the crystalline Chlorophyll of Borodin. If methyl alcohol 

 is used, methyl chlorophyllide is formed in the same way. If, how- 

 ever, the action is carried out in moist acetone or ether, the phytyl 

 group is hydrolyzed off and the free carboxyl group results, thus 

 giving chlorophyllide. 



The reverse reaction may also be carried out. When free chlo- 

 rophyllide a and phytol were mixed and allowed to stand 24 hours 

 with meal of leaves rieh in chlorophyllase, it was found that at least 

 20 percent of the chlorophyllide had been converted into Chloro- 

 phyll a. If a little water is present the amount of Chlorophyll 

 formed corresponds to 60 percent of the chlorophyllide, while 65 

 percent seems to be the point of equilibrium. 



Crystalline Chlorophyll.^« Borodin^^ in 1881 obtained a 



18 Willstätter and Benz: Ann. d. Chem., 358, 267 (1907). 



19 Borodin: Bot. Zeitung, 40, 608 (1882). 



