78 DISACCHARIDES, POLYSACCHARIDES AND GLUCOSIDES 



plished, by the interaction of potassium fructosate and acetochlor- 

 glucose. 1 



Cane-sugar is not attacked by any ferments excepting Invertase, 

 an enzyme found in many yeasts, moulds, and in some of the higher 

 plants. Invertase, as its name implies; effects the hydrolysis of 

 cane-sugar into its constituent parts, glucose and fructose; that is, 

 it brings about "inversion." Cane-sugar, or, rather, its product, 

 glucose, does not undergo alcoholic fermentation in the presence of 

 yeasts until it is broken down into glucose and fructose. Hence yeasts 

 which do not contain invertase are not able to cause alcoholic fer- 

 mentation in solutions of cane-sugar. 



Maltose is a disaccharide which results from the hydrolysis of starch 

 or of glycogen by acids or by ferments. Acids, however, continue the 

 process of hydrolysis by splitting the maltose itself, so that maltose 

 is only a transient stage in the hydrolysis of starch or glycogen by acids. 

 On the other hand the ferments which split starch or glycogen do not 

 hydrolyze maltose, so that if maltose-splitting ferments be absent 

 the process of hydrolysis ceases at this stage. 



Maltose is highly dextrorotatory, exhibits, mutarotation, reduces 

 Fehling's solution and forms a phenylosazone. When hydrolyzed by 

 acids it yields two molecules of glucose, but it is much less readily 

 hydrolyzed by acids than cane-sugar. The ferment Diastase, which 

 hydrolyzes starch and glycogen, the ferment Invertase which hydrolyzes 

 cane-sugar, the ferment Lactase which hydrolyzes milk-sugar, and the 

 ferment Emulsion which hydrolyzes amygdalin and isomaltose, are all 

 without action upon maltose, which is hydrolyzed only by a ferment 

 known as Maltase, found in many animal tissues and in the majority of 

 yeasts. Maltose itself does not undergo alcoholic fermentation, and 

 must first be split by maltase or by acids into glucose, but as the 

 majority of yeasts contain maltose, these yeasts can accomplish the 

 reduction of alcohol from maltose. 



The glucose which maltose yields upon hydrolysis is initially highly 

 rotatory; on adding ammonia the rotation falls. Hence maltose is a 

 derivative of a glucose. It is, in fact, glucose-/* glucoside. It can, 

 of course, exist in two forms, according to whether the glucose moiety 

 which still contains a potential aldehyde group is in the a or )8 form. 

 The one maltose, a-maltose, is therefore a-glucose-a-glucoside; the 

 other is /3-glucose-a-glucoside. 



Maltose can be synthesized from glucose by the condensing action 

 of strong acids. But in addition to maltose another disaccharide is 

 obtained by this process. This disaccharide is isomeric with maltose 

 and yields, like maltose, two molecules of glucose on hydrolysis, 

 differs from maltose in the characteristics of its phenylosazone, and 

 also in the fact that it is not fermentable by yeasts. The ferment 

 maltase, in fact, has no action upon it, while the ferment emulsion, 



1 Marchlcwski in 1899. 



