Linked Life Data

365531

Source:http://linkedlifedata.com/resource/pubmed/id/365531

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1979-3-28
pubmed:abstractText
The sigmoidal shape of the curve for v[S], characteristic of pyruvate decarboxylase, indicates that the catalytic activity of this enzyme is regulated by the substrate. The enzyme, which is inactive in the absence of its substrate, is activated not only by 2-oxo acids but also by 2-oxo acid amides, which cannot act as a substrate of the enzyme. Whilst the dissociation constant of the enzyme-activator complex depends on the electrophilic nature of the carbonyl group, the catalytic activity reached at saturation concentrations of the activator species is independent of the structure of the activator molecules. The mechanism of activation which proceeds via two reversible steps could be evaluated exactly by stopped-flow techniques. The kinetic parameters of the activation and deactivation reaction were estimated and the validity of the equations derived which describe the activation kinetics could be proved by comparing them with the measured data. Using glyoxylic acid as an irreversibly binding active-site marker, it could be shown that addition of the substrate to the enzyme-bound thiamin diphosphate is the step of the catalytic mechanism whose rate is controlled by the substrate (activator) molecule.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
175-81
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
The mechanism of substrate activation of pyruvate decarboxylase: a first approach.
pubmed:publicationType
Journal Article