ANTI-ENZYME IMMUNITY 203 



Velluz (1938) observed that carbon disulfide detoxifies tetanus 

 toxin, not diphtheria toxin, the difference being ascribed to the absence 

 of SH groups in the latter. Diphtheria toxin contains 0.75 per cent 

 sulfur, but fails to give the nitroprusside test for SH (Pappenheimer, 

 1937). This amount of sulfur corresponds to about 20 molecules of 

 cysteine per molecule of toxin of 72,000 molecular weight. 



Pillemer, et al. (1938) found that urease oxidized by cuprous oxide 

 and air is reactivable with reducing agents, H2S and KCN. Although 

 oxidized urease has lost its specific reactivity with antiserum to crys- 

 talline active urease, oxidized and reduced urease elicited similar anti- 

 bodies. This was explained by the fact that whole blood was unable, 

 but tissue extracts were capable of reactivating oxidized urease, which 

 indicated that the oxidized urease is made specifically antigenic in the 

 animal tissue. Pillemer, et al. (1939) converted keratins (wool, chicken 

 feathers, human hair) into their sulfhydryl derivatives (kerateines), 

 and the latter were oxidized to obtain di-thiol derivatives (meta- 

 keratin). Immunologically it was found that species specificity is an 

 individual characteristic of the keratin. Optimal species specificity was 

 demonstrated only when the reduced keratin (kerateine) was allowed 

 to react with the antiserum prepared by the injection of the homologous 

 kerateine. Thus, immunological differences among the keratins were 

 detectable depending on the state of oxidation or reduction of the 

 SH groups in the proteins. Using a similar approach, Ecker and Pille- 

 mer (1940) found immunological species differences between the 

 ocular lens proteins of chicken and fish (pike). Similar proteins from 

 swine and sheep lenses behaved as if identical. Reduced swdne lens 

 protein contained 8.5 per cent sulfur, and those from the other three 

 animals from 4.3 to 5.2 per cent. In anaphylactic tests, Markin and 

 Kyes (1939) found species differences between the lens proteins of 

 dog and beef and that from the pigeon lens. 



The above results would seem to show that sulfhydryl and disulfide 

 groupings play significant roles in certain enzyme reactions as well as 

 in the specificity of certain antigenic proteins and toxins. 



