i9o8] 



POND—SOI.VTION TENSION AND TOXICITY 



234 



be more readily saponified by the lipase. A 0.01 25 jxr cent, solution 

 of the enzyme yielded from o. 10"^ of butyrate enough acid to recjuire 

 o. 20'"^^ of m/20 KOH for neutralization. The .same concentration of 

 enzyme acting for one hour longer at the same temperature on the 

 same amount of acetate gave the figure 0.06' '" of w/40 KOII. A 

 stronger .solution of the enzyme (0.0250 per cent.) acting on the acetate 

 gave 0.08''' of }n/j\o ivOH. From this one miglit think that the 

 butyrate is the less stable in the presence of the enzyme, but it may 

 be that the products of saponification are more inhibiting in the one 

 case than in the other. The concentration of the enzvme in mo.st of 



TABLE I: Relative toxicity with same concentration of enzyme 

 Potassium and sodium in contemporaneous test 



POTASSIUM 



SODIUM 



Enzyme 0.05 per cent. Incubation 5 hours at 40^ C 



8 In the column headed "w" are given the various concentrations of the to.xic 

 sail in fractions of molecular strength. In this column ihe word "Water" means 

 that 2CC of water were used instead of the toxic solution in order to ascertain the un- 

 inhibited activity of the enzyme in 0.05 per cent, strength. In the column headed 

 "Control" are given the figures for the final acidity (cc. OT/40 KOH) of the boiled 

 preparations containing the toxic salt in the concentration indicated by the correspond- 

 ing figure in the column headed ";«." The column headed "Enzyme" shows the 

 final acidity of the unboiled preparations corresponding to the controls. The column 

 headed "Increase" shows the difference in acidity between the controls and the un- 

 boiled preparations and expresses the amount of saponification allowed by the con- 

 centration of the toxic solution indicated by the corresponding figures in the column 

 headed " m." 



