MALTASE. 525 



by chloroform water, it may be mentioned that, according to 

 MORRIS (III.), fresh, intact yeast, unlike dried yeast, will not 

 decompose maltose. It transpired, however, that MORRIS (IV.) 

 had employed chloroform water to prevent fermentation during 

 the digestion of the yeast with maltose, which reagent, according 

 to EMIL FISCHER (XII.), and also LINTNER and KROBER (I.), 

 seriously injures or destroys maltase. EMMERLING (XII.) states 

 that maltase is unaltered by light. 



All these experiments show that maltase is a far more sensi- 

 tive enzyme than invertase. It is apparently unnffected by yeast 

 tryptase, BAU (XXVI.) having found that low-fermentation yeast 

 TJF liquefied in five hours at 45 C., exerted a fairly powerful de- 

 composing action on maltose, whilst, on the other hand, no maltase 

 could be detected in expressed yeast juice that had been kept for 

 eight days at about 20 0., or in another sample of the same 

 juice three weeks old. The conditions causing the disappearance 

 of this enzyme were not investigated : and a profitable field is 

 therefore still open for the fermentation physiologist to extend 

 our knowledge on yeast maltase. 



Special interest also attaches to maltase, inasmuch as it 

 exhibits not merely hydrolytic properties, but also acts as a 

 synthetic agent. C. HILL (I.) found that, in presence of larger 

 quantities of maltose, the decomposition of this sugar remains 

 incomplete as soon as the solution has become enriched in glucose. 

 Hill prepared his maltase solution by drying low-fermentation 

 beer yeast on earthenware plates and heating the pulverised mass 

 gradually to 100 C., the powder being digested with a tenfold 

 quantity of a weak solution of sodium carbonate for three days, 

 in presence of toluene. The filtrate completely decomposed a 

 2 per cent, solution of maltose, but not stronger solutions. The 

 presence of glucose also hindered the complete hydrolysis of the 

 maltose. When Hill allowed the maltase solution to act on a 

 40 per cent, solution of glucose, reversion was observed, 15 per 

 cent, of the sugar being converted into a disaccharide, which Hill 

 regarded as maltose. By means of experiments extending over 

 several months, 0. EMMERLING (XIII.), however, showed that the 

 reversion sugar is not maltose but isomaltose, namely, FISCHER'S 

 (XIII.) unfermentable isomaltose, and not that of 0. J. LINTNER 

 (XLVIL). These two isomaltoses are fundamentally different 

 kinds of sugar, which merely have the same empirical composi- 

 tion, are derived from d-glucose and furnish identical phenylosa- 

 zones melting at 151- 153 C. Unfortunately, we cannot here go 

 into the much-discussed question of the existence of Lintner's 

 isomaltose ; but that of Fischer's isomaltose is regarded by 

 FISCHER (XIV.) and OST (II.) as definitely established. Emmer- 

 ling's claim that Fischer's isomaltose is formed by the action of 

 yeast maltase was disputed by HILL (II.); but, after EMMER- 

 LING (XII.) had succeeded in reconstructing amygdalin from 



