Enzymic basis for the nutritional requirement of arginine in insects.

The fat body of the cockroach, Blaberus cranifera, and the silkmoth, Hyalophora gloveri, has been tested for some enzymes of the urea cycle. While ornithine transcarbamoylase and argininosuccinase activities could not be detected, arginase is present in the fat body of these insects. These results explain the essentiality of arginine in the diet of insects.