title: Biosynthesis of polyamines in ornithine decarboxylase, arginine decarboxylase, and agmatine ureohydrolase deletion mutants of Escherichia coli strain K-12.
abstract: Escherichia coli K-12 mutants that carry deletions in their genes for ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) (speC), arginine decarboxylase (L-arginine carboxy-lyase, EC 4.1.1.19) (speA), and agmatine ureohydrolase (agmatinase or agmatine amidinohydrolase, EC 3.5.3.11) (speB) can still synthesize very small amounts of putrescine and spermidine. The putrescine concentration in these mutants was found to be 1/2500th that in spe+ cells. The pathway of putrescine synthesis appears to be through the biodegradative arginine decarboxylase, which converts arginine to agmatine, in combination with a low agmatine ureohydrolase activity--1/2000th that in spe+ strains. These results suggest that even such low levels of polyamines permit a low level of protein synthesis. Evidence is presented that the polyamine requirement for the growth of the polyamine-dependent speAB, speC deletion mutants, which are also streptomycin resistant, is not due to a decreased ability to synthesize polyamines.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D005796:Genes; D005798:Genes, Bacterial; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011073:Polyamines / Q000096:biosynthesis*; D011700:Putrescine / Q000096:biosynthesis; D012329:RNA, Bacterial / Q000096:biosynthesis; D013307:Streptomycin / Q000494:pharmacology; D014512:Ureohydrolases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011073:Polyamines; D012329:RNA, Bacterial; D014512:Ureohydrolases; C019625:agmatinase; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; C019722:arginine decarboxylase; D011700:Putrescine; D013307:Streptomycin