Decarboxylases for polyamine biosynthesis in Drosophila melanogaster larvae.

Ornithine decarboxylase (L-ornithine carboxy-lase, EC 4.1.1.17) and S-adenosyl-methionine decarboxylase (S-adenosyl-L-methionine carboxy-lase, EC 4.1.1.50) were assayed in Drosophilia melanogaster larvae. The highest enzyme activities were detected in 24 and 48 h larvae, with diminishing activities in subsequent larval stages. Stimulation of S-adenosylmethionine decarboxylase by putrescine was demonstrable in late but not in early stages of larval development.