ANTI-ENZYME IMMUNITY 



353 



intestine of guinea pig and that this inhibitory effect by toxin is neu- 

 trahzed by antitoxic sera. 



The suspension of the minced small intestine of a guinea pig 

 oxidized succinate, p-phenylenediamine and dihydroxyphenylenedi- 

 amine. The following substances were found to be non-oxidizable by 

 the enzyme suspension: glucose, fructose, sucrose, lactate, pyruvate, 

 fumarate, malate, oxalate, butyrate, oxalacetate, citrate, formate, 

 glycerol, alanine, serine, tryptophane, glutamate, aspartate, phenyl- 

 alanine, glycylglycine, leucylglycine, glycyltryptophane or glycyl- 

 tyrosine. 



The toxins of CI. oedematiens, CI. septique, CI. tetani, and CI. 

 welchii, types A, B, C, and D were similarly tested. Of these, only the 

 toxins of CI. welchii produced inhibitions significantly greater than 

 that of the broth precipitate, and of these inhibitions, that induced by 

 the type A organism was the greatest and that by the type D the least. 

 The extent of the inhibition varied with the amount of toxin added. 

 At the concentration of 0.4 mg. of toxin per system, the inhibition by 

 the toxins of the A, C, D types of organisms were respectively 84.21, 

 64.01 and 29.48 per cent. a-Toxin was present in all of these three 

 toxins. The /3-toxm was only present in the toxin of type C organism 

 (100 toxin units per 100 mg.) and the e-toxin only in that from type 

 D (800 units of toxin/100 mg.) and, in comparison with a-toxin, their 

 concentrations were high. On the basis of comparative studies, the 

 authors suggested that the inhibition of the succinate oxidation may 

 be due to the a-toxin, but that, in any case the inhibitory actions of 

 the )8- and e-toxins must be small. 



The toxin of CI. welchii caused a 39 per cent inhibition of the oxida- 

 tion of dihydroxyphenylalanine, and 27.42 and 84.32 per cent inhibi- 

 tion, respectively, of phenylenediamine and succinate. These are 

 known to be specific substrates for the cytochrome-cytochrome-oxi- 

 dase (indophenoloxidase) respiratory systems. 



The oxidation of succinate by other tissues was studied and it was 

 found that the toxin of type A CI. welchii caused 21 .66 to 74.0 per cent 

 inhibition of the succinate oxidation by skeletal and heart muscles, 

 liver, kidney and brain tissues. A dried preparation of 'lactic dehydro- 

 genase,' which oxidized succinate much more actively than lactate 

 or malate, was also inhibited about 80 per cent by various toxins. In 

 contrast, in experiments of a preliminary nature, no inhibitory effect 



