ENZYME-SUBSTRATE COMPOUNDS 



complex I are observed spectrophotometrically up to very 

 high peroxide concentrations would provide evidence that the 

 formation of complex I is so rapid that no other intermediate 

 tlian complex I would have tiine to be forined in the reaction. 



Pushing 

 Block 



Syringe 

 Plunger 



Syringe 



Stopcock 



Supporting 

 Franne 



Beaker to 

 receive 

 residual HpOp 



Fig. 1. Quenching type of Hartridge-Roughton flow apparatus used 

 for the investigation of catalase activity at high hydrogen peroxide concen- 

 trations (17). 



A pair of 2-mI. tuberculin-type syringes contain, respectively, 1-5 M H2O2 

 and about 10' A/ enzyme. Enzyme and substrate are forced into the mixing cham- 

 ber by the pushing block and flow down the reaction tube a distance corresponding 

 to 0.1 to 0.4 sec. Sulfuric acid is then rapidly mixed to stop the reaction. The 

 remaining peroxide is back titrated with permanganate (FA-20). 



311 



