Linked Life Data

222326

Source:http://linkedlifedata.com/resource/pubmed/id/222326

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1979-9-25
pubmed:abstractText
The formation of the ternary complex of lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) from pig heart and skeletal muscle with the adduct of pyruvate to NAD", spin-labeled at N6 was studied by ultraviolet spectroscopy and ESR techniques. According to ultraviolet measurements we found identical binding characteristics for the natural coenzyme and its spin-labeled analog. The rate by which the ESR signal of free spin-labeled NAD+ decreased upon addition of pyruvate to the binary complexes was substantially different in the two isozymes. With the heart type an initial drop followed by a further linear decrease, zero order in the enzyme and coenzyme concentration was observed. In case of the skeletal muscle isozyme no immediate reaction and a first order process occurred. The initial reaction can be attributed to a non-covalent enzyme/spin-labeled NAD+/pyruvate complex with a dissociation constant for pyruvate of 11 +/- 1 mM, thus explaining the well-known substrate inhibition in the heart isozyme above 2 mM pyruvate. The further reaction is then determined by the buffer dependent enolization of pyruvate. In the muscle isozyme formation of the covalent adduct is not assisted by prior binding of pyruvate in a non-covalent ternary complex and therefore the rate depends on the binary complex concentration.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
567
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49-59
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
The nature of the substrate inhibition in lactate dehydrogenases as studied by a spin-labeled derivative of NAD.
pubmed:publicationType
Journal Article, Comparative Study