228 PHARMACEUTICAL BACTERIOLOGY 



it occurs principally in bitter almonds, in the leaves of Laurocerasus and in 

 the seeds of the Rosaceae. Among the cryptogams emulsin is found in 

 Aspergillus niger, Penicillum glaucum and in many other species of higher 

 fungi and also among the bacteria. 



Emulsin, also known as synaptase, splits amygdahn into grape sugar, 

 benzaldehyd and hydrocyanic acid, in the presence of water. It is most 

 active' at 4S°-So° C, and is destroyed at 70° C, although in the dry state 

 it can resist a temperature of 100° C. for several hours. It is destroyed by 

 alkalies whereas acids merely inactivate it. It also decomposes the 

 glucosides arbutin, salicin, helicin, gentiopicrin, syringin, phyllirin, cyclamin 

 apiin and convallarin. It does not act on populin, solanin, hesperidin, 

 convallaramin, convolvulin, digitaUn, hederin and quercitrin. Emulsin 

 is said to decompose lactose into glucose and galactose, thus resembhng 

 lactase in its action. 



b. Myrosin. — This is the ferment active in mustard and also in other 

 cruciferous plants. It acts (in the presence of water) upon the glucoside 

 of mustard, sinalbin, converting it into mustard oil, dextrose and sinapin 

 sulphate. 



c. GauUkerase. — This enzyme was first discovered in Gaultheria and 

 named gaultherase; but it is also present in Betula species, Spiraa 

 ulmaria, S. filipendula, in Monotropa hypopiiys and in other plants. It 

 acts only upon the glucoside gaultherin (abundant in Gauhheria pro- 

 cumbens). It does not act on salicin or amygdalin, thus differing from 

 emulsin. 



d. Rhamnase. — A ferment which is said to occur in the seeds of 

 Rhamnus infectoria and which acts upon the glucoside xanthorhamnin, 

 decomposing it into rhamnin (rhamnetin) and glucose. Boiling destroys 

 the ferment converting it into rhamniose (a trisaccharid) and other 

 products. 



Indigo formation is supposed to be due to the action of a glucoside 

 spHtting ferment but this has not yet been proven. It is known that 

 Indican (the glucoside of Indigof era and Isatis species) is decomposed into , 

 indiglucin and iadigwhite in the presence of chloroform water, whereas 

 boihng destroys such action, this tending to prove that the ferment is not 

 of bacterial origin as was once supposed. 



Other glucoside splitting ferments probably exist in plants, as for 

 example in the cucumber. Ecballium elaterium contains a ferment which 

 presumably spUts up the glucoside elaterin and which may be called 

 eleterase. 



5. Fat Splitting Ferments. — ^As is known fats are esters of glycerin. 

 Under the influence of the fat splitting ferments the fats are decomposed 

 into free fatty acids, and glycerin. The fat enzymes have been long 



