Chinese Journal of Physiology

ACID- AND BASE-BINDING POWER OF PROTEINS 15

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Fig. 4. Change in base-binding power of denatured egg albumin on coagulation.

Combind effect of denaturation and coagulation of egg albumin.—The procedure in these experiments was the same as that described above, except that in some solutions the amount of acid or alkali used was not enough to prevent coagulation. The results of two experiments are shown in tables 5-6 and figs. 5-6.

The results of these experiments confirm those in which denaturation and coagulation were studied separately. At and about the isoelectric point the effect of coagulation predominates over that of denaturation. In more acid or alkaline solutions, the reverse is the case. At two points, one on either side of the isoelectric point, the effects of denaturation and coagulation just balance each other and no change in pH was obesrved.

This is shown perhaps more clearly in another experiment in which the total acid or alkali contents of different solutions were not equalized before measuring the pH, but a control was prepared for each of the heated solutions. The results of this experiment are shown in table 7 and fig. 7, In areas I and IV the effect of denaturation predominates over that of coagulation, while in areas II and III the reverse is the case,