528 



E. BOERI AND M. RiPPA 



where Wj is the molar concentration of each ion and z, is its valence. The 

 ionic strength was arranged by adding increasing amounts of sodium chloride 

 to the solution. It appears that a definite ionic strength is needed for the 

 reaction. At high ionic strength the reaction rate decreases slowly again. 



pH 



Fig. 5. The effect of pH on the rate of the reaction. Abscissa: time in minutes. 



Ordinate: activity in fractions of the maximal (at pH 7). Phosphate buffer: 



0-01 M. Other conditions are as in Fig. 1. 



— ) 



-< 



20 



30 



Fig. 6. The effect of the ionic strength 

 on the reaction rate. Abscissa: time in 

 min. Ordinate: oxygen consumption. 

 The number near each tracing indicates 

 the ionic strength. Enzyme added: 14 

 m/imoles. Other conditions as in Fig. I . 



Fig. 7. The effect of the ionic 

 strength on the reaction rate. 

 Abscissa: ionic strength. Ordin- 

 ate: oxygen consumption in 13 

 min. Enzyme added : 14 m/^moles. 

 Other conditions as in Fig. 1. 



The Effect of the Addition of CataJase 



In order to ascertain whether the oxidation of lactate occurs through 

 formation of hydrogen peroxide, catalase was added. As it appears from 



