XIII. SULFONAMlDi; JvlOVi;i£8AL 73 



The extent to which compounds related to PABA in structure reverse 

 sulfonainitle inhil)ition of iiacleria is summarized in Table IX. 



With tiie inlormation of the preceding paragraphs forming the essential 

 "framework" for a "working hypothesis" of the fate of PAliA within the 

 cell as revealed by studies employing sulfonamides, some of the more con- 

 troversial aspects of the sul)ject as well as further details of the scheme 

 may be examined. 



Although it has been almost universally agreed for some time that sul- 

 fonamides act by inhibiting the conversion of PABA to folic acid, the 

 exact locus of this effect has not been established. 



on COOH 



C N 



/ \ / \ 

 N C C 



CH2NH— <C >— CONHCHCH2CH2COOH 



C CH 



/\ / \ / 

 H2N N N 



Folic acid 



A logical point for interference is the conjugation of PABA with glutamic 

 acid. If this condensation is interfered with by sulfonamides, then sul- 

 fonamides should be ineffective in the presence of p-aminobenzoylglutamic 

 acid. With the exception of the results of Auhagen,*^^ who reported that 



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