K. G. FALK AND G. McGUIRE 599 



actions were observed, but, in view of possible experimental errors, 

 these apparent actions were not of sufficient magnitude to prove 

 conclusively the presence of such an enzyme. The object of the 

 preliminary treatment with alcohol (Method 6) was for the purpose 

 of dissolving possible inhibiting substances, such as tannin, with 

 the simultaneous precipitation of the enzyme in order to obtain 

 the latter separated from inactivating soluble material. The 

 tests for sucrase were positive, considerable action being obtained. 

 Since the ripe banana could be handled more readily, a more extended 

 and quantitative examination of the sucrase from this source will be 

 reported. 



A few of the results with the unripe banana preparations are given 

 to show the nature of the actions. 20 gm. of pulp obtained by 

 Method 4 with 10 cc. of 2 per cent starch solution after 21 hours at 

 32°C. gave reducing substances corresponding to 5.0 mg. of CU2O 

 per gm. of pulp, and with 10 cc. of 20 per cent sucrose solution simi- 

 larly, the reducing substances corresponding to 246 mg. of CU2O per 

 gm. of pulp. 20 gm. of pulp plus peel mixture obtained by Method 5 

 treated similarly gave with the starch no reducing substances, and 

 with the sucrose reducing substances corresponding to 203 mg. of 

 CU2O per gm. of pulp plus peel. 



The results of Bailey* on the action of air on the green banana pulp 

 were confirmed, no amylase being obtained by this treatment. 



Soluble Sucrase Preparation from Ripe Bananas. 



Soluble and insoluble sucrase preparations were obtained from ripe 

 bananas. As a result of a number of different methods of extrac- 

 tion, the following procedure was found to give the most satisfactory 

 soluble preparation. The banana pulp was ground rapidly in a food 

 chopper, the finest cutter being used, then mashed in a porcelain 

 mortar with a wooden potato masher with normal sodium chloride 

 solution (100 cc. for each 400 gm. of pulp). Toluene was added and 

 the mixture then filtered through paper. The filtrate was dialyzed 

 18 to 24 hours in collodion bags against running water to remove 

 the salt, soluble dialyzable carbohydrates, and other products. The 

 resulting solution was used in the sucrase experiments. 



