454 Enzyme Action 
that oxidizing enzymes were inhibited by bromides. All these 
investigations were made with rather strong concentrations of 
salts; and nothing, so far as we are aware, has been published 
on the question of the action of bromates upon the enzymes, tryp- 
sin and pancreatin. An investigation of this point was there- 
fore undertaken at the request of the Ward Baking Company of 
New York. 
Effects on Trypsin. 
The technique of the trypsin experiments was as follows: A 
buffer solution was prepared, made up of 40 cc. of 0.067 mM KzHPO,, 
10 cc. of 0.067 Mm KH2PO,, and 50 ce. of water; pH value 7.1. 
Definite amounts of casein and trypsin were added as stated in 
the protocol of the individual experiments, and to a series of 
bottles of the resulting solution were added varying amounts of 
potassium bromate. The bottles were then incubated at 37°C. 
for the periods stated in the protocols. 
At the end of the incubation period the amino-acid content of 
each bottle was determined by the following method, and the ex- 
cess produced by the action of the trypsin found by subtracting 
* the amino-acid content of a control containing casein alone. 
Each bromate dilution was tested in triplicate. 
Method of Titration. 
1. Add phenolphthalein to incubated solution. 
2. Add Ba(OH),. (saturated solution) to deep red color—removal of 
phosphates. 
3. Pour into graduated cylinder. 
4, Rinse incubation bottle with small quantity of distilled H.O. Pour 
rinsings into cylinder. 
5. Make up to 100 ec. with distilled H.O. 
6. Filter through paper into bottle. 
7. Measure off 50 cc. of filtrate and pour into cylinder. 
8. Neutralize to faint pink with 0.2 n HCl. 
9. Add 0.2 n NaOH to desired+titration color. 
10. Add 15 cc. of neutralized HCHO. 
11. Titrate with 0.2 n NaOH to same color as in (9). 
12. Express results in terms of cc. of 0.2 N NaOH to neutralize after 
addition of neutralized HCHO. 
In a series experiment, preserve control by addition of CHCl, 
and keeping in a dark place. 
