CLASSIFICATION OF ENZYMES 265 



it is found that each one of them is capable of acting on but one 

 or a few substances. The characteristic action of an enzyme is 

 its power to induce chemical changes in an amount of material 

 vastly disproportionate to its own bulk. Diastase is able to hy- 

 drolyze ten thousand times its own bulk of starch and invertin 

 may convert a hundred thousand times its bulk of cane-sugar into 

 invert sugar. Enzymes are quickly destroyed by the blue violet 

 rays of light and are not active below a temperature of freezing, 

 and each reaches a specific optimum at a point between 30 and 

 50 C. and all are destroyed at a temperature below 100 C. 

 when moist. 



336. Classification of Enzymes. The following classification of 

 enzymes is made by Green on the basis of the character of the 

 material acted upon. 1 



ENZYMES acting upon carbohydrates producing soluble sugars. 

 Diastases attack starch and related substances. Inulase decom- 

 poses inulin. 



CYTASE, hydrolyzes the celluloses of which walls are com- 

 posed. 



ENZYMES which transform sugar of the biose type into simpler 

 sugars, usually hexoses. Invertase attacks cane-sugar. Glucose 

 splits up maltose. 



ENZYMES which decompose glucosides, of which emulsin and 

 tyrosin are examples. 



ENZYMES which decompose proteids, among which are pepsin 

 and trypsin probably identical with the substance of the same 

 name in animal digestion. 



ENZYMES which produce jelly-like substances from soluble 

 liquids, including rennet, thrombase, and pectase. 



ENZYMES which attack oils and fats of which but one has been 

 determined, lipase. 



'OXIDASES which oxidize various substances inclusive of coloring 

 matters. The best known oxidases are laccase and tyrosinase. 



Many other fermentative processes that can not be ascribed to 



1 Green, J. R. Fermentation. Cambridge. 1899. 



