Linked Life Data

172510

Source:http://linkedlifedata.com/resource/pubmed/id/172510

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1976-3-1
pubmed:abstractText
Activation of membrane-associated thiamin triphosphatase from rat brain requires a divalent cation (Mg2+, Ca2+, or Mn2+). The optimum concentration of Mg2+ necessary for maximal enzyme activity varies with substrate concentration; conversely, the maximal rate of hydrolysis attainbale by increasing thiamin triphosphate concentration is directly proportional to [Mg2+] for all levels of Mg2+ below that of the substrate. Under appropriate conditions, the Km of the thiamin triphosphatase for Mg2+ and for thiamin triphosphate are shown to be identical. Dissociation constants (Kd) for the binding of Mg2+ to thiamin triphosphate, thiamin diphosphate, and thiamin were determined; kinetic data re-expressed in terms of [Mg2+-thiamin triphosphate] conform to simple single substrate predictions, suggesting that the true enzyme substrate may be the Mg2+-thiamin triphosphate complex. Excess free Mg2+ inhibits thiamin triphosphatase activity competitively while excess free thiamin triphosphate in concentrations up to 10 times Km has no effect on the membrane-bound enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
251
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
Membrane-associated thiamin triphosphatase. II. Activation by divalent cations.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.