536 ENZYMES DECOMPOSING SACCHARIDES. 



and with the glucose radical in the other, so that the oxygen 

 combination, indicated by thick type, can easily be resolved by 

 invertase in both instances. 



LINDNER (XXXV.), however, objected that certain yeasts are 

 able to ferment raffinose, but not saccharose, and that therefore 

 the existence of a raffinase cannot be disputed. As an instance, 

 mention may be made of Schizosaccharomyces octosporus which, 

 according to E. FISCHER and LINDNER (IY.), contains raffinase 

 but not invertase. On the other hand, Lindner's film yeasts 

 No. 170 and 178 will ferment saccharose, leaving ramnose intact. 

 In the case of animal invertase, PAUTZ and VOGEL (I.), as also 

 E. FISCHER and NIEBEL (I.), found that the enzyme from 

 the intestinal mucous membrane of dogs and horses will decom- 

 pose saccharose, leaving raffinose unaltered. 



From these statements, the existence of raffinase may be 

 assumed to be demonstrated ; but all that we know about it, 

 apart from the fact that it splits up raffinose into cZ-fructose and 

 melibiose, is that as observed by Bau it is decomposed at a 

 temperature of 75 C., and is contained in Merck's invertase. 

 According to GILLOT (V.), raffinase occurs in mould fungi, as well 

 as in yeasts. 



In the case of polysaccharides, according to BOURQUELOT 

 (XI V.), the enzymes act successively, so that in our case, the 

 raffinose must first be hydrolysed by raffinase, before the melibiase 

 can act on the liberated melibiose. No reversion takes place, and 

 melibiase cannot attack raffinose itself. 



In addition to raSInase which merits exhaustive investiga- 

 tion there are certainly other enzymes that are able to split up 

 the polysaccharides; but as even less is known about these 

 enzymes than about raffinase, we cannot devote a separate 

 paragraph to them, and therefore they are briefly reviewed below. 



Thus, it is doubtful whether the manna-trisaccharide, which 

 TANRET (VI.) found in the manna of the ash-tree, is partially or 

 completely hydrolysed by yeast, or not attacked at all. 



The reports on the fermentation of melecitose by yeasts also 

 require confirmation. According to BOURQUELOT and HERISSEY 

 (III. and V.), this sugar is decomposed by an enzyme of Aspergillus 

 niger, into glucose and turanose. This latter sugar, a biose, 

 composed of two <:Z-glucose groups, may also be formed by the hydro- 

 lysis of melecitose by acids. 



BOURQUELOT (XV.) states that only one-third of gentianose is 

 fermented by yeast, the latter separating c-fructose and ferment- 

 ing that sugar, but leaving the gentiobiose behind. However, 

 under the influence of an enzyme of Aspergillus niger, and also of 

 emulsin, gentiobiose can be split up, by further hydrolytic action, 

 into two molecules of ^-glucose. 



A tetrasaccharide, stachyose, which was specially investigated 

 by TANRET (VI.) and by A. VON PLANTA and E. SCHULZE (I.), is 



