MOLECULAR COMPLEMENTARINESS IN ANTIGEN-ANTIBODY SYSTEMS 13 



TABLE 5 

 Specificity of charged groups in the NN 



AsOsH" system 



Hapten 



o 



AsO- 

 OH 







so- 







C 



-X CH, 

 ^AsO- 

 -/ O 



0- 



PO 

 OH 



OH 



OH 



SbOH 



OH 



o- 



KJ 



1.0 



1.0 



system has already been described as being loose with the antibodies essen- 

 tially of the slit trench form. 



The specificity of the antibody with respect to the nature of the charged 

 group is very important; this is illustrated in Table 5 (Pressman, Pardee and 

 Pauling, 1945). Antibody specific to the />ara-azobenzenearsonate group was 

 studied and it was found that the phosphonate group was essentially as effec- 

 tive as the arsenate group. However, other charged groups, some of even 

 smaller size, were unable to replace the arsenate group efifectively. Thus, sul- 

 fonate, carboxylate, methyl arsenate, and stibonate did not combine. 



In a carboxylate system, i.e., antibodies against the benzoate ion, similar 

 specificity is observed in that antibody will not combine with sulfonate ion or 

 arsenate ion, but requires the carboxylate ion for combination. 



I should like to mention at this time that it is not necessary to have a charged 

 group for specificity to exist against haptens. Specificity against uncharged 

 groups also occurs (Landsteiner, 1945). 



Just how closely antibody fits around the charged group was determined by 

 experiments involved in combination of antibody to the ^ara-azobenzene-tri- 



