Abstract
Summary
1. The inactive principles of an extract of gastric mucosa can be activated to various degrees by varying the degree of original activity.
2. The activity developed at a given degree of acidity can be destroyed by 30 minutes' exposure to a weakly alkaline solution and cannot be restored on acidification to a point below or equivalent to the original H-ion concentration.
3. Further activity can be demonstrated by acidifying to higher degrees than the primary acidity.
4. The proportionate loss in digestive power is greater, upon making the solution alkaline, the higher the degree of preliminary acidity.
5. The activity shown by an acidified extract of gastric mucosa is dependent in part upon the actual amount of active enzyme present.
6. The effect of alkalinity upon the unactivated extract is to lower the resultant activity after acidification. The effect increases rapidly with increasing alkalinity, and all digestive action may be lost around pH 12 to pH 13.
7. Except for the very slight alkalinity of pH 8.00, this destruction by alkali is rapid, reaching its maximum in a few minutes.
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