K. G. FALK AND G. McGUIRE 607 



tion.i* Repeating his work, using the most satisfactory method of 

 obtaining active preparations which he described, as well as extracts 

 obtained as described with the sucrase experiments and incubating 

 with 1 per cent Lintner starch solution for 24 to 40 hours at 30° to 

 35°C., it was found that no amyloclastic actions as marked as those 

 described by Bailey were obtained. The greatest change which was 

 observed in any of the tests was a change from the deep blue iodine 

 starch reaction to a bluish violet color test. The amyloclastic actions 

 may therefore be said to be extremely small if present at all. In all 

 these tests, toluene was used as preservative. 



DISCUSSION. 



The change of soluble sucrase material into insoluble during the 

 simple treatment of dialysis raises the question of the state of the 

 sucrase in the growing banana. On grinding to a pulp and extract- 

 ing, soluble and insoluble preparations were obtained. This treat- 

 ment may, however, have been sufficient to change materially the 

 properties of the substances originally present. It is therefore con- 

 ceivable that the sucrase may be present as a completely soluble sub- 

 stance in the ripening fruit and that the differences in solubility 

 observed were due entirely to the treatment to which the fruit was 

 subjected. It must also be recalled that toluene was added when- 

 ever the treatment extended over a greater period of time than a few 

 minutes and that this toluene may exert a definite influence, possibly 

 of a coagulating nature, upon the substances present. 



This change in solubility was also observed when the bananas were 

 ground in a ball mill with toluene present. 8 hours grinding followed 

 by extraction gave a certain amount of soluble sucrase although less 

 than was obtained by grinding in a mortar for a shorter period of 

 time. Grinding for a week, however, resulted in the extract showing 

 no sucrase action at all. The residue showed marked activity. It 

 is probable that here, too, the soluble sucrase was converted into 

 insoluble material. The reasons or causes for this change, whether 

 due to dialysis and removal of certain products, the action of toluene, 

 or other cause, are not known but will be investigated further. 



^^ Cf. similar observations with potato amylase.® 



