Polyamines(e.g, spermidine and spermine), needed for DNa packaging, is made from Met and ornithine Nitric oxide(NO), a stable free radical signals for vasodilation(血管舒张) in vertebrates, is made from the guanidino group of Arg and O, in a reaction catalyzed by an monooxygenase, nitric oxide synthase (NOs nos is a dimeric enzyme with each subunit containing an array of redox coenzymes: NADP FMN, FAD, tetrahydrobiopterin, and Fest-heme• Polyamines (e.g., spermidine and spermine), needed for DNA packaging, is made from Met and ornithine. • Nitric oxide (NO), a stable free radical signals for vasodilation (血管舒张) in vertebrates, is made from the guanidino group of Arg and O2 in a reaction catalyzed by an monooxygenase, nitric oxide synthase (NOS). • NOS is a dimeric enzyme with each subunit containing an array of redox coenzymes: NADP, FMN, FAD, tetrahydrobiopterin, and Fe3+ -heme