12 DYNAMICS OF LIVING MATTER 



Hill raises the question, as to whether or not a synthetical forma- 

 tion of maltose under the influence of maltase may occur in the living 

 cell. He points out that for such a result a high concentration of 

 dextrose in the blood is by no means necessary; that it is sufficient 

 if the product of the synthesis is removed immediately, possibly 

 through a further synthesis into a higher carbohydrate by another 

 enzyme in the cell. In this way the concentration of the maltose is 

 kept at zero, and the tendency toward the establishment of the chemical 

 equilibrium must favor the further synthesis. 



The synthesis of sugar into glycogen is of general importance, inas- 

 much as glycogen is the form in which the carbohydrates are stored 

 in our liver and muscles. Max Cremer* immediately after the appear- 

 ance of Hill's paper published the important observation, that the juice 

 pressed out from yeast, which had previously been rendered free from 

 glycogen, is capable of forming glycogen from sugar. When 10 per 

 cent of a fermentable sugar was added to the juice, the latter gave the 

 glycogen reaction after from twelve to twenty-four hours, but this 

 result was not obtained in all cases. 



It may perhaps not be unnecessary to call attention to the fact that 

 in all the cases we have discussed the enzymes are soluble substances, 

 which can be extracted from the cells, and therefore can exist inde- 

 pendently of the life or structure of the cell from which they are 

 obtained. 



In the group of proteins we not only meet with the same difficulties 

 which are found in the group of carbohydrates, but also with the addi- 

 tional difficulty, that we know considerably less about the constitution 

 and configuration of the various protein molecules than of the carbo- 

 hydrates. These two conditions probably account for the fact that 

 a direct reversion of the action of a hydrolytic enzyme has not yet been 

 satisfactorily proven for proteins. 



It is hardly necessary to mention especially the fact that hydro- 

 lytic enzymes, e.g. of the type of trypsin, acting on proteins, are found 

 not only in the intestine, but also in tissues, probably generally. Thus 

 Salkowski has shown that if yeast cells or muscles are kept aseptically 

 in an incubator, an autodigestion occurs in which leucin and tyrosin, 

 i.e. typical end products of proteolysis, are formed. 



Kutscher f has completed the proof by showing that, in addition 

 to the acids, the other end products of proteolysis are formed in the 

 autodigestion of yeast; namely, the hexonbases, e.g. arginin and lysin. 

 He found, moreover, that in starving yeast the above-mentioned end 



* Cremer, Ber. der deut. chem. Gesell., Vol. 32, p. 2062, 1899. 



f Kutscher, Hoppe-Seyler's Zeitsch. fur physiolog. Chemie, Vol. 32, p. 59, 1901. 



