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.     

Examination of the large white and small white butterflies (Pieris spp.) for the presence of mustard oils and mustard oil glycosides

Sinigrin and mustard oils were identified in the pupae of the large white butterfly (Pieris brassicae) and the small white (P. rapae). It is assumed that these substances are sequestered by the larvae from its foodplant and stored. The large white is apparently the more efficient storer of the two, and mustard oils could be detected in the adults, as well as the larvae.     

The possible correlation between cathepsin activity and protein synthesis

The cathepsin activity of different rat organs has been compared with their capacity for amino acid uptake. These data, together with the cathepsin activity of mice submaxillary glands under different conditions of protein synthesis, suggest a relation between cathepsin activity and protein synthesis.     

Cardiac glycosides in a scale insect (Aspidiotus), a ladybird (Coccinella) and a lacewing (Chrysopa)

The presence of cardiac glycosides in the body tissues of three species of insects from three different orders, all feeding on Nerium oleander L., is recorded.