I'iiANsAcWoJis OF sticJrioM fi. 



671 



))0»'tion of maltose within the limits of Kjeldahrs ' Law of Proportionality.' The 

 following results were obtained : — 



The order of these results was several times confirmed, and in some cases 

 larger percentage increases were obtained when acting on starch paste with the 

 filtrate from the mixed barley and malt. The experiment recorded above makes 

 it evident that the increased activity of the tilti-ate on the mixture is making itself 

 felt principally in the directioa of the hydrolysis of the starch paste, which is 

 evidence that if an enzyme has been liberated it is one that facilitates lique- 

 faction of starch to a far greater degree than saccharification of already soluble 

 starch. 



It is, of course, possible that in the filtrate from the mixture of barley and 

 malt the malt portion may have contributed liquefying diastase in sufficient 

 quantity nut only for the liquefaction of the starch paste — it is itself saccharifying — 

 but suliicieut also for the liquefaction of more than this amount, which would 

 then be available for attack by the saccharifying diastase of the barley, and thus 

 the mean of their actions would appear in excess of the theoretical amount. It 

 is obvious that if this is the case we should get the enhanced effect by mixing- 

 the filtrates of the separately extracted malt and barley in equal proportions and 

 carrying out a conversion with the mixture. When this is done, however, the 

 maltose formed is the exact mean of that obtained from the two solutions used 

 separately. 



These experiments, so far as they go, show that there is an undoubted increase 

 in the diastatic activity of barley when digested in the presence of the enzymes of 

 malt. This increased activity, whether due to the presence of a proteolyst or not, 

 is exercised mainly in the direction of the liberation of starch-liquefying enzyme. 



We are continuing this investigation, as we believe it may be the means of 

 throwing further light upon some of the processes associated with germination. 



9. The Preparation of Pure Maltose. 

 By Julian L. Baker, F.I.C., and F. E. Day. 



In a paper on the Action of Ungerminated Barley Diastase on Starch ' one of us 

 showed tLat tlie sole products of the action of barley diastase on starch paste or 

 soluble starch were maltose, about 60 per cent., and u-amylodextrin. The dextrins 

 accompanying starch conversions made with malt diastase are soluble in alcohol, 

 and it is by no means an easy matter to isolate the maltose in a state of purity. 

 In starch conversions made with barley diastase a-amylodextrin can be easily 

 separated from the maltose by one precipitation with alcohol, and this constitutes 

 a convenient method for isolating pure maltose. The conversion is carried out by 

 preparing a quantity of a 3 per cent, starch paste or a 3 per cent, sol-atiou of 

 soluble starch and adding precipitated barley diastase, prepared according to 

 Liutner's directions,- in such proportion that for every gram of starch the enzyme 

 from 1 gram of barley is present. The hydrolysis of the starch is conducted at a 

 temperature of 50° C. for five or six hours, and allowed to run on for several hours 

 in the cold. The conversion is evaporated to a thin syrup and poured into so much 



» Chem, Soo. Trans., 1902, 81, 1177. 



J. PrAk. Chem., 1886 (ii.), 34, 378. 



