The decarboxylation of l-ornithine to yield putrescine, catalyzed by the l-ornithine decarboxylase (EC 4.1. 1.17) of E. coli, and the decarboxylation of l-arginine to yield agmatine, catalyzed by the l-arginine decarboxylase (EC 4.1. 1.19) of E. coli, take place with