CARBOHYDRATE ENZYMES 61 



pearance of arginine and at the same time the formation of ornithine 

 or urea. But guanine is not decomposed by the arginase of the yeasts. 



Straughn and Jones 1 have found guanase by centrifuging aqueous 

 extracts of yeasts made according to the following: 300 grams of 

 yeast were macerated for 15 hours in a liter of water to which 6 c.c of 

 chloroform had been added. The liquid thus obtained could transform 

 guanine into xanthine and therefore contain guanase; it could not 

 change adenine into hypoxanthine nor hypoxanthine into xanthine. 

 Consequently it did not contain adenase nor xanthooxidase 



According to H. Pringsheim 2 there exists in yeasts a special de- 

 amidase, which permits them to take nitrogen from amino acids 

 without the production of ammonia indicating a preliminary decom- 

 position. Finally, Effront has recently discovered in top beer yeasts 

 an amidase which acts also on amino acids but produces ammonia 

 and volatile acids. 



Lipase 



The existence of a lipase in the cell sap which transforms fats 

 into fatty acids and glycerol, has been shown. This lipase seems to 

 exert an injurious action on the zymase. This seems to be composed 

 of a proteolytic enzyme, properly speaking, and of a coferment. 

 Lipase decomposes the coferment. 



Lipase seems to be intracellular and acts on the fats which it en- 

 counters within the protoplasm of the yeast, especially during sporula- 

 tion, which are the reserve products for the cell during maturation 

 of the ascospores. 



In certains yeasts, however, lipase is able to diffuse through 

 membranes, for van Tieghem has discovered, some time ago, S. olei 

 which lives in oil and decomposes it. More recently Piedallu 3 has 

 found a yeast which lives in oil and offers the same properties. Rogers 

 and Jensen 4 have mentioned very many Torula which decompose 

 butter. 



Carbohydrate Enzymes 



The investigations of Fischer and Thierf elder 5 have shown that 

 only the sugars with carbon atoms in multiples of three are ferment- 



1 Straughn, N., and Jones, W. The nuclein ferments of yeasts. Jour. Biol. 

 Chem. 6, 1909. 



2 Pringsheim, H. Ueber Pilzdesamidase. Biochem. Zeitschr. 12, 1908. 



3 Piedallu, A. Sur une levure qui agit sur les corps gras. Comp. Rend. 

 Soc. de Biol. 65, 1908. 



4 Jensen, O. Bakteriologische Studien iiber danische Butter. Cent. Bakt. 29, 

 1911. 



5 Fischer, E., and Thierf elder, H. Verhalten der verschiedenen Zucker gegen 

 reine Hefen. Berichte d. deutsch. Gesellschaft, 27, 1894. 



