108 



A SYMPOSIUM ON RESPIRATORY ENZYMES 



the coenzyme by adsorption on the copper sulfide. For desorption 

 the sulfide precipitate is aerated until slight oxidation of copper 

 sulfide is attained. This method of desorption, the details of which 

 were described some years ago (9, 14), has also proved advantageous 

 in preventing losses by adsorption on silver sulfide. The final puri- 

 fication is brought about by fractional barium and lead precipitation. 

 Both codehydrogenases prepared according to the methods given 

 in Tables 2 and 3 contain traces of impurities which complicate 

 their use in the spectrographic methods employed in dehydrogenase 

 investigations. The great stability toward oxidizing agents (le) per- 

 mits the destruction of impurities by treatment with bromine water 



Table 4.— Properties of codehydrogenases I and II 



