Linked Life Data

11350776

Source:http://linkedlifedata.com/resource/pubmed/id/11350776

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2001-5-14
pubmed:abstractText
Methionine metabolism forms homocysteine via transmethylation. Homocysteine is either 1) condensed to form cystathionine, which is cleaved to form cysteine, or 2) remethylated back to methionine. Measuring this cycle with the use of isotopically labeled methionine tracers is problematic, because the tracer is infused into and measured from blood, whereas methionine metabolism occurs inside cells. Because plasma homocysteine and cystathionine arise from intracellular metabolism of methionine, plasma homocysteine and cystathionine enrichments can be used to define intracellular methionine enrichment during an infusion of labeled methionine. Eight healthy, postabsorptive volunteers were given a primed continuous infusion of [1-13C]methionine and [methyl-2H(3)]methionine for 8 h. Enrichments in plasma methionine, [13C]homocysteine and [13C]cystathionine were measured. In contrast to plasma methionine enrichments, the plasma [13C]homocysteine and [13C]cystathionine enrichments rose to plateau slowly (rate constant: 0.40 +/- 0.03 and 0.49 +/- 0.09 h(-1), respectively). The enrichment ratios of plasma [13C]homocysteine to [13C]methionine and [13C]cystathionine to [13C]methionine were 58 +/- 3 and 54 +/- 3%, respectively, demonstrating a large intracellular/extracellular partitioning of methionine. These values were used to correct methionine kinetics. The corrections increase previously reported rates of methionine kinetics by approximately 40%.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0193-1849
pubmed:author
pubmed:issnType
Print
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
E947-55
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Measurement of intracellular sulfur amino acid metabolism in humans.
pubmed:affiliation
Departments of Medicine and Chemistry, University of Vermont, Burlington, Vermont 05405, USA.
pubmed:publicationType
Journal Article, Clinical Trial, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't