Table 3— Preparation of codehydrogenase I from yeast 



YEAST 



Extracted with HjO at 80-100° C. 



|+Pb(Ac)2 



SOLUTION 



+Ba(Ac)2+NaOH (pH 8) 



PRECIPITATE (discarded) 



SOLUTION 



+phosphotungstic acid 



PRECIPITATE (discarded) 



SOLUTION (discarded) 



PRECIPITATE 



suspended in dilute H2SO4 

 +amyl alcohol-ether 



H2O-H2SO4 PHASE 



+Ba(0H)2 (BaS04 i ) 

 +AgN03+NH40H (pH 7.5) 



AMYL ALCOHOL-ETHER PHASE 

 (discarded) 



PRECIPITATE 



|H2S(Ag2S i ) 



SOLUTION (discarded) 



SOLUTION 



l +CuCl in concentrated KCl+ HCl 



SOLUTION (discarded) PRECIPITATE 



+H2S (CU2S i ) 

 concentration in vacuo 

 alcohol precipitation 



CODEHYDROGENASE I (60-80 per cent purity) 

 IHjO, Ba(0H)2 (pH 8) 



SOLUTION 



+H2SO4 (BaS04 i ) 



+Pb(Ac)2 



PRECIPITATE (discarded) 



PRECIPITATE 



(adenylic acid and 

 impurities) 



SOLUTION 



fractional precipitation by alcohol 



FRACTION 1 FRACTION 2 ^^^F.SS:^ a 



IHoS (PbS i ) IH2S (PbS 1 ) H2S (PbS i ) 



Ualcohol l+alcohol +alcohol 



i i i T 



CODEHYDROGENASE I CODEHYDROGENASE I CODEHYDROGENASE I 



(80-90 per cent) (90-100 per cent) (90-100 per cent) 



107 



