The influence of pH on the enzymatic decarboxylation of oxalacetic acid

The pH-activity curve of the oxalacetic carboxylase of Cucurbita pepo seeds which catalyzed the decarboxylation of oxalacetic acid was examined for the possible factors whose variation with pH might be responsible for the shape of the curve between pH 3.5–5.0.

1.

1. It was shown that the shape of the curve remains essentially the same regardless of whether the reactions were conducted in buffers of constant ionic strength or of constant molarity. However, ionic strength had a definite effect on the over-all rate of the enzymatic reaction.