The Enzymic Degradation of Starch and Glycogen

The Enzymic Degradation of Starch and Glycogen 1. Action of Amylase 

After earlier workers had indicated the existence of several amylases in malt, conclusive evidence that the malt amylase is composed of at least two starch-splitting enzymes was furnished by Ohlsson. Both enzymes are capable of attacking starch and glycogen, but their action is very different. One enzyme, termed saccharogenic amylase by Ohls- 

The saccharification of potato starch with pure /3-amylase yields 61 % of maltose and not more. In a series of experiments we obtained as the mean value from the reduction, 61.1 %, and from the fermentation experiments, 60.8%. The reduction was (as in most experiments in this laboratory) determined by a modification of the iodometric method of 

Blom and coworkers have found the limit of saccharification to be 53% at pH 3.4. Higher values are attributed to traces of a-amylase. This question has been exhaustively discussed by Hopkins.It should be pointed out that a different degree of saccharification at different pH s seems understandable if one assumes that the influence of the proximity of branching points or other anomalies on the /3-amylase varies with the pH. Hopkins and Cooper find the limit value 56%. They point out that barley amylase very often is contaminated with amylases from bacteria or moulds present on the grains. 

The /3-amylase liberates the maltose in the /S-configuration. This is no proof for the occurrence of /3-D-glucosidic linkages in starch. On the other hand, it is not known why the /3-amylase, in contrast to the a-amylases, causes an inversion of the configuration. 

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Myrback, Karl, Products of the Enzymic Degradation of Starch and Glycogen, III, 251-310... 

Karl MyrbAck, Products of the Enzymic Degradation of Starch and Glycogen 252 M. Stacey and P. W. Kent, The Polysaccharides of Mycobacterium tuberculosis 311 R. U. Lemieux and M. L. Wolfrom, The Chemistry of Streptomycin. 337... 

Maltose is 4-a-D-glucopyranosyl-p-D-glucopyranose. It is the major end product of the enzymic degradation of starch and glycogen by p-amylase and has a characteristic flavor of malt. Maltose is a reducing disaccharide, shows mutarotation, is fermentable, and is easily soluble in water. 

PRODUCTS OF THE ENZYMIC DEGRADATION OF STARCH AND GLYCOGEN 295 4. Action of Taka-amylase ... 

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