Linked Life Data

7499215

Source:http://linkedlifedata.com/resource/pubmed/id/7499215

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
1996-1-17
pubmed:abstractText
To elucidate the catalytic mechanism of monodehydroascorbate (MDA) reductase from cucumber, its interaction with MDA radical was investigated by the use of pulse radiolysis. When approximately equimolar MDA radical to the fully reduced MDA reductase was generated, the fully reduced enzyme reacted first with MDA radical to form the red semiquinone, and the semiquinone further reacted with MDA radical to form the oxidized enzyme. At a low ratio (< 20) of MDA radical to enzyme concentration, the fully reduced enzyme reacted quantitatively with MDA radical to form the semiquinone with a second-order rate constant of 2.6 x 10(8) M-1 s-1 at pH 7.4. At excess MDA radical to enzyme concentration, a similar rate constant was obtained from the decay of MDA radical. These results suggest that the reaction of the semiquinone with MDA radical occurs at the same rate or rate-limiting step of the oxidation of the fully reduced enzyme by MDA radical. The rate constants decreased with an increase in NaCl concentration, suggesting that the localization of cationic groups of amino acid residue near the active site may provide electrostatic guidance to the anionic substrate of MDA radical.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27551-4
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
A direct demonstration of the catalytic action of monodehydroascorbate reductase by pulse radiolysis.
pubmed:affiliation
Institute of Scientific and Industrial Research, Osaka University, Japan.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't