CHEMISTRY. 257 



method as a means of determining progress, experiments upon the isolation 

 of the enzyme were undertaken in 1910, and in 191 1 preparations of pan- 

 creatic amylase having about eight times the activity of any amylase pre- 

 viously described were obtained. As this appeared to be a definite product, 

 its chemical nature and amylolytic power were studied, as fully as the avail- 

 able amount of purified material would permit, and the results were pub- 

 lished (Sherman and Schlesinger, Journal American Chemical Society, July 

 191 1 and August 1912). This amylase was able to digest at least 1,000,000 

 times its weight of starch and to form over 500,000 times its weight of sugar. 



With the aid of the grant a similar study of the purification and properties 

 of the amylase of malt was begun in January 1912 and is being actively 

 carried on. Miss M. D. Schlesinger, to whose cooperation the success of 

 the study of pancreatic amylase was so largely due, is devoting her time 

 to this work. The method which had given best results in the purification 

 of pancreatic amylase was found not to be applicable to the amylase of malt, 

 but other methods of the same general nature have been developed and have 

 already yielded several independent preparations having at least two to three 

 times the activity of the strongest malt amylase previously described — a 

 preliminary result which is gratifying in view of the short time in which it 

 has been obtained. 



In connection with these experiments upon purification, preliminary data 

 have been obtained upon the chemical nature and activity of this enzyme, the 

 relation between its amyloclastic and its saccharogenic powers, the influence 

 of certain salts upon its activity, and its comparative stability in different 

 solvents and under different precipitants used in its purification. Utilizing 

 the knowledge of properties thus obtained, further experiments are being 

 made with a view to determining in detail the exact method of purification 

 which shall yield a uniform product of the highest possible activity. Only 

 by the study of such a preparation can the long-disputed question of the 

 chemical nature of this important enzyme be settled. Such preliminary 

 observations as have been practicable in connection with the preparations 

 already made point strongly toward a substance of essentially protein nature, 

 as was indicated by Osborne in 1895. Further observations upon the chem- 

 ical nature and properties of the malt amylase are being made as rapidly as 

 the purified material can be prepared, and it is hoped that a general descrip- 

 tion of the purified amylase of malt (corresponding to the description of the 

 pancreatic amylase already published) may be ready for publication, and a 

 similar purification of a fungus amylase begun by the middle of 1913. It is 

 planned to emphasize the comparative feature throughout the investigation. 

 Differences in behavior already observed between the three typical amylases 

 selected for study furnish important evidence for the view that these are 

 different substances. This evidence, however, can be made conclusive only 

 by a systematic comparative study of these amylases in the highest possible 

 state of purity. 



