ANTIBODY AS A SPECIFIC ENZYME INHIBITOR 153 



not the other. a-Glucosidase will attack the a- and not the ^-linkage 

 and /?-fructosidase will attack the 13- and not the a-linkage in saccha- 

 rose. This is illustrated in the following manner: 



Saccharose =a-Glucose^ y/5-Fructose 



f '^ 



a-Glucosidase /3-Fructosidase 



Raffinose=o-Galactose<f a-Glucose<^ y/3-Fructose 



f ^« 



a-Galactosidase p-Fructosidase 



Melezitose=a-Glucose^ /3-Fructose^ ^-Glucose 



r V 



a-Qlucosidase a-Glucosidase 



In this connection it may be mentioned that an enzyme from sweet 

 almond capable of hydrolyzing ^-d-glucuronide will not hydrolyze 

 i3-d-glucoside. It is therefore clear that in this case /^-configuration is 

 not the only essential condition for the specific action of an enzyme. 

 Similarly, /?-glucosidase will hydrolyze /S-glucoside and not ^-galacto- 

 side. Hypothetically it is assumed that /3-glucosidase might hydrolyze 

 at different rates both /8-glucoside and /?-galactoside, which might be 

 interpreted to indicate a relative specificity of ^S-glucosidase towards 

 y3-galactoside. The evidence for this assumption, however, is still very 

 weak (Helferich, 1933, 1938). 



3. Comparison of the Stereoisomeric Specificities of Im- 

 mune and Enzyme Reactions 



Comparing the specificity of the reaction between an antibody and 

 the homologous antigen containing a glucoside with the specific action 

 of a glucosidase on a glucoside substrate, the following facts are evi- 

 dent. As previously suggested by others (Marrack, 1938) we will 

 arbitrarily compare the antibody with the enzyme, and the antigen 

 with an enzyme substrate. Avery and Goebel (1929), and Goebel, 

 Avery and Babers (1934) showed that the antiserum against ^-gluco- 

 side did not react with the antigen containing ^S-galactoside; and the 

 antiserum against the i8-galactoside did not react with the test antigen 

 containing )8-glucoside. Table IV likewise shows that the enzyme /?- 



