title: Oxidation of L-thiazolidine-4-carboxylate by delta1-pyrroline-5-carboxylate reductase in Escherichia coli.
abstract: L-Thiazolidine-4-carboxylate (T4C, thiaproline) is a sulfur-containing proline analog that stimulates the immune system in aging mice and inhibits urinary tract pathogens such as Escherichia coli. A constitutive NADP+-dependent T4C dehydrogenase activity was detected in the soluble fraction of a putA::Tn5 mutant of E. coli lacking l-proline dehydrogenase and partially purified by ammonium sulfate precipitation, dye-affinity chromatography on Cibacron Blue 3GA agarose, and ion-exchange chromatography on DEAE-cellulose. At each step in the purification, T4C dehydrogenase activity copurified with Delta1-pyrroline-5-carboxylate (P5C) reductase activity. E. coli strains with greatly reduced P5C reductase activity due to a proC mutation had no detectable T4C dehydrogenase activity. Although P5C reductase did not act on proline, it also catalyzed the oxidation of 3,4-dehydroproline. These results suggest that this biosynthetic enzyme may play a role in the degradation of proline analogs and limit the clinical efficacy of these compounds.
authors.affiliation: Department of Biological Sciences, University of Nevada, Las Vegas, NV 89154, USA. cdeutch@elmira.edu
authors.forename: C E
authors.initials: CE
authors.lastname: Deutch
authors.forename: J L
authors.initials: JL
authors.lastname: Klarstrom
authors.forename: C L
authors.initials: CL
authors.lastname: Link
authors.forename: D L
authors.initials: DL
authors.lastname: Ricciardi
mesh_terms: D000818:Animals; D000975:Antioxidants; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D051379:Mice; D009154:Mutation; D010084:Oxidation-Reduction; D011758:Pyrroles / Q000378:metabolism*; D011762:Pyrroline Carboxylate Reductases / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D013844:Thiazoles / Q000378:metabolism*; D053778:Thiazolidines; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase
chemical_list: D000975:Antioxidants; D011758:Pyrroles; D011762:Pyrroline Carboxylate Reductases; D013844:Thiazoles; D053778:Thiazolidines; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase; C015485:delta-1-pyrroline-5-carboxylate; C003438:thiazolidine-4-carboxylic acid