CH. VIII.] MALTASE, ETC. 221 



portion of the deposit in A under the microscope and note the 

 characteristic crystals of the glucosazone. In B the sugar produced 

 is maltose, the osazone of which does not separate in the boiling 

 water bath. 



265. The action of pancreatic maltase. Measure 10 cc. of a 

 2 per cent, solution of maltose into two tubes, C and D. To C add 

 2 cc. of the pancreatic extract and a little toluol. Boil 2 cc. of the 

 extract, cool and add it to D, together with a little toluol. Stopper 

 the tubes and incubate for 24 to 48 hours at 38 to 40 C. Prepare 

 the osazones as described in the previous exercise. C generally gives 

 a fair yield of glucosazone. In D there is no separation whilst hot, 

 but on cooling slowly the characteristic crystals of maltosazone 

 separate out (Ex. 122). 



I. Maltase, Lactase and Sucrase. 



These enzymes hydrolyse the three chief disaccharides 

 into their constituent monosaccharides. They are all found 

 in the succus entericus and the mucous membrane of the 

 small intestine. Maltase is also present in pancreatic 

 extracts (see above). 



By the action of these enzymes the sugars of the food 

 and those formed by the action of ptyalin and amylopsin 

 in starch are converted to glucose, fructose and galactose 

 before absorption. The disaccharides themselves are 

 never found in the blood, and if injected they are rapidly 

 excreted in the urine. 



266. Maltase. To 50 cc. of a 2 per cent, solution of maltose 

 add 10 cc. of the extract of pig's intestine (see p. 218) and a little 

 toluol. Transfer to a small flask labelled E, stopper, shake well, and 

 incubate for 24 to 48 hours (or longer) at 38 C. Boil 10 cc. of the 

 extract and cool under the tap. Add it to another 50 cc. of the 

 maltose, label the flask F, add toluol, and incubate as a control. 



With 10 cc. of E and F proceed to prepare the osazones as 

 directed in the previous exercise. E generally gives a good yield of 

 glucosazone, whilst the solution is still hot, whilst F only yields the 

 maltosazone on cooling. 



