Linked Life Data

19762467

Source:http://linkedlifedata.com/resource/pubmed/id/19762467

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
2009-11-25
pubmed:abstractText
Trichomonas vaginalis is a protozoan parasite of humans that is able to synthesize cysteine de novo using cysteine synthase but does not produce glutathione. In this study, high pressure liquid chromatography analysis confirmed that cysteine is the major intracellular redox buffer by showing that T. vaginalis contains high levels of cysteine ( approximately 600 mum) comprising more than 70% of the total thiols detected. To investigate possible mechanisms for the regulation of cysteine levels in T. vaginalis, we have characterized enzymes of the mercaptopyruvate pathway. This consists of an aspartate aminotransferase (TvAspAT1), which transaminates cysteine to form 3-mercaptopyruvate (3-MP), and mercaptopyruvate sulfurtransferase (TvMST), which transfers the sulfur of 3-MP to a nucleophilic acceptor, generating pyruvate. TvMST has high activity with 3-MP as a sulfur donor and can use several thiol compounds as sulfur acceptor substrates. Our analysis indicated that TvMST has a k(cat)/K(m) for reduced thioredoxin of 6.2 x 10(7) m(-1) s(-1), more than 100-fold higher than that observed for beta-mercaptoethanol and cysteine, suggesting that thioredoxin is a preferred substrate for TvMST. Thiol trapping and mass spectrometry provided direct evidence for the formation of thioredoxin persulfide as a product of this reaction. The thioredoxin persulfide could serve a biological function such as the transfer of the persulfide to a target protein or the sequestered release of sulfide for biosynthesis. Changes in MST activity of T. vaginalis in response to variation in the supply of exogenous cysteine are suggestive of a role for the mercaptopyruvate pathway in the removal of excess intracellular cysteine, redox homeostasis, and antioxidant defense.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
27
pubmed:volume
284
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
33485-94
pubmed:dateRevised
2011-3-3
pubmed:meshHeading
pubmed-meshheading:19762467-Amino Acid Sequence, pubmed-meshheading:19762467-Animals, pubmed-meshheading:19762467-Chromatography, High Pressure Liquid, pubmed-meshheading:19762467-Cysteine, pubmed-meshheading:19762467-Electron Transport, pubmed-meshheading:19762467-Kinetics, pubmed-meshheading:19762467-Mass Spectrometry, pubmed-meshheading:19762467-Molecular Sequence Data, pubmed-meshheading:19762467-Oxidation-Reduction, pubmed-meshheading:19762467-Oxidoreductases, pubmed-meshheading:19762467-Protozoan Proteins, pubmed-meshheading:19762467-Sequence Homology, Amino Acid, pubmed-meshheading:19762467-Substrate Specificity, pubmed-meshheading:19762467-Sulfhydryl Compounds, pubmed-meshheading:19762467-Sulfides, pubmed-meshheading:19762467-Sulfur, pubmed-meshheading:19762467-Sulfurtransferases, pubmed-meshheading:19762467-Thioredoxins, pubmed-meshheading:19762467-Trichomonas vaginalis
pubmed:year
2009
pubmed:articleTitle
The mercaptopyruvate sulfurtransferase of Trichomonas vaginalis links cysteine catabolism to the production of thioredoxin persulfide.
pubmed:affiliation
Strathclyde Institute of Pharmacy and Biomedical Sciences, Univesity of Strathclyde, Glasgow G4 0NR, United Kingdom. gareth.westrop@strath.ac.uk
pubmed:publicationType
Journal Article