Oxidation of L-thiazolidine-4-carboxylate by delta1-pyrroline-5-carboxylate reductase in Escherichia coli

C E Deutch, J L Klarstrom, Casey L Link, D L Ricciardi

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)442-6
Number of pages5
JournalCurrent Microbiology
Issue number6
StatePublished - Jun 2001


  • Animals
  • Antioxidants
  • Escherichia coli/enzymology
  • Mice
  • Mutation
  • Oxidation-Reduction
  • Pyrroles/metabolism
  • Pyrroline Carboxylate Reductases/genetics
  • Substrate Specificity
  • Thiazoles/metabolism
  • Thiazolidines

PubMed: MeSH publication types

  • Journal Article


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