ENZYMES. 65 



very long time and concluded from the change in rotation and reduction 

 power that some maltose was formed from the dextrose. EMMERLiNG 1 

 showed afterward that a synthesis of maltose did not occur, but rather 

 an isomeric carbohydrate, isomaltose was formed, which is not split by 

 maltase. According to ARMSTRONG 2 emulsin splits isomaltose, but 

 not maltose, and therefore it can synthesize maltose from dextrose. A 

 similar reaction had previously been shown by E. FISCHER and ARM- 

 STRONG, 3 that kefir-lactase produced isolactose and not lactose from 

 galactose and dextrose. According to CREMER 4 yeast-press juice has 

 the power of forming glycogen from dextrose or levulose. 



Of the enzymotic syntheses of protein-like substances nothing pos- 

 itive is known. Although it has been repeatedly claimed that the forma- 

 tion of plastein is a synthetical process, still the proofs for this are lack- 

 ing. It is just possible that we are here dealing with the simultaneous 

 precipitation of two or more digestion products. 



A true reformation of a subtrate once split seems for the present 

 not to have been proven for the carbohydrates and proteins. Such a 

 synthesis of amygdalin is nevertheless known. Amygdalin is split by 

 maltase into mandelic acid nitrileglucoside and dextrose. EMMERLING 5 

 has been able to reconstruct amygdalin from these products with the aid 

 of maltase, and recently ROSENTHALER 6 reports that he has formed a 

 so-called asymmetrical synthesis whereby from benzaldehyde and hydro- 

 cyanic acid under the influence of emulsin the d-form of the mandelic 

 acid nitrile (C6H 5 CH(OH).CN) is formed. An undoubted synthesis 

 of fat and other ester-like combinations of fatty acids is also known. 

 KASTLE and LOEVENHART 7 have shown the formation of ethyl butyrate 

 fr,om ethyl alcohol and butyric acid under the influence of a pancreas 

 enzyme. In an analogous manner HARRIOT 8 obtained monobutyrin 

 from butyric acid and glycerin with blood serum. POTTEVIN 9 by means 

 of a pancreas enzyme transformed oleic acid and glycerin into mono- 

 and triolein as well as oleic acid esters with monatomic alcohols. The 

 synthetical action of the pancreas has been closely studied by DIETZ. I() 

 The enzyme used by DIETZ was insoluble in water, and its action was 



1 Ber. d. d. chem. Gesellsch., 34, 600 and 2207, 1901. 



2 Proc. Roy. Soc. (ser. B), 76, 592, 1905. 



3 Ber. d. d. chem. Gesellsch., 35, 3151, 1902. 



4 Ibid., 32, 2062, 1899. 



5 Ber. d. d. chem. Gesellsch., 34, 3810, 1901. 

 Bioch. Zeitschr., 14, 238, 1908. 



7 Amer. chem. Journ., 24, 491, 1900. 



8 Compt. rend., 132, 212, 1901. 



9 Ibid., 136, 1152, 1903; 138, 378, 1903; Ann. Inst. Past., 20, 901, 1906. 



10 Zeitschr. f. physiol., Chem., 52, 279, 1907. 



