Effect of Substrate Concentration-Within certain limits, the total initial
amount of perborate present is without effect on the amount of perborate
destroyed. The maximum concentration of substrate is limited by the
solubility of the sodium perborate. The lower limit varies somewhat with
the concentration of enzyme and the time of incubation, but in no tissue
or set of circumstances tested did a reduction of 20 per cent in the initial
amount of substrate affect the assay result. In the case of previously
untested tissues, this simple procedure may be used as a criterion of ade-
quacy
of substrate.