Linked Life Data

3706736

Source:http://linkedlifedata.com/resource/pubmed/id/3706736

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1986-6-16
pubmed:abstractText
A method for determination of 4-methylthio-2-hydroxybutyrate and 4-methylthio-2-oxobutyrate in human urine has been devised, based on metoxime formation of the keto acid and a clean-up procedure using a strong anion-exchange resin AG 2 X 8 and ethyl acetate extraction. After alkylation, the compounds were quantified by GC, using a flame photometric sulfur-selective detector. A normal urinary excretion of 0.14 to 0.25 mmol/mol creatinine and 0.07 to 0.22 mmol/mol creatinine of the alpha-hydroxy and alpha-keto acid, respectively, was found, whereas a markedly elevated excretion of the hydroxy acid was noted in subjects with hypermethioninemia. The enzymatic reduction of 4-methylthio-2-oxobutyric acid by lactate dehydrogenase: NAD+ oxidoreductase (EC 1.1.1.17) was also studied. The Km and Kequil values for 4-methylthio-2-oxobutyrate were 1.41 mM and 0.92 X 10(8) M-1. The Vmax value of the enzyme at infinite concentrations of the two substrates was 7.2 mumol/s/mumol enzyme, which indicates low affinity and reduced catalytic activity compared to other known substrates of lactate dehydrogenase. The reaction product 4-methylthio-2-hydroxybutyrate was not inhibitory on the reaction. The M4 isoenzyme of lactate dehydrogenase (rabbit and pig muscle) possessed approximately 20% of the activity of the H4 isoenzyme (pig heart) for the substrate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0003-2697
pubmed:author
pubmed:issnType
Print
pubmed:volume
154
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
43-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
The occurrence of 4-methylthio-2-hydroxybutyrate in human urine.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't