ACTION OF DIASTASE ON STARCH 219 



Action of Diastase on Various Forms of Starch. The 

 utilization of complex carbohydrates by the body is clearly a 

 very complicated process as was believed. Sigmund Lang 

 confirmed this in his comparative studies upon the influence 

 of pancreatic diastase upon starches from different sources, 

 showing that oats starch, which is highly resistive to catabol- 

 ism into products which do not give a color reaction with 

 iodine, is very readily converted into sugar; that potato 

 starch, conversely, while very readily decomposed into 

 achroodextrin, is converted into sugar only very slowly. 

 This behavior of oats starch to diastase is scarcely con- 

 sonant with the strikingly favorable results obtained by the 

 * ' oats treatment ' ' employed by v. Noorden for diabetes. On 

 the other hand, it is questionable whether it is really proper, 

 as is usually done at the present time, to make the disappear- 

 ance of the iodine reaction the basis of quantitative de- 

 termination of the effect of diastase, and whether it would 

 not be better, as Lang proposes, to estimate the effectiveness 

 of diastasic ferments from the amount of end-product, 

 glucose, than from such arbitrary intermediate product. In 

 the end it is undoubtedly the end-product which concerns the 

 requirements of the body. 84 It is well to recall here besides 

 that the individual phases of starch cleavage are by no means 

 well known, and that the "dual enzyme theory" (strongly 

 opposed by plant physiologists) is still a matter of dispute 

 (this theory assuming that diastase is not a single ferment 

 but is composed of two different enzymes, maltase and 

 dextrinase). 85 



Attempts to "isolate" diastase have failed of satisfac- 

 tory result, precisely as in the case of other ferments. 86 In 

 contrast, the physical-chemical behavior of diastase is ap- 

 parently an inexhaustible mine of notable observations. 



M S. Lang (F. Kraus's Med. Clinic, Berlin), Zeitschr. f. exper. Pathol. und 

 Ther., 8, 1910, s. a. 



85 Literature : C. Oppenheimer, Die Fermente, 3d ed., Ill, pp. 84-86, 1910. 



86 S. Frankel and M. Hamburg, Hofmeister's Beitr., 8, 389, 1906; E. Pribram 

 (Frankel's Lab. ) , Biochem. Zeitschr., U, 293, 1912. 



