Linked Life Data

1551865

Source:http://linkedlifedata.com/resource/pubmed/id/1551865

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1992-4-28
pubmed:abstractText
Steady state kinetic analysis at pH 7.0 of the reduction of DL-glyceraldehyde by pig muscle aldose reductase showed that the enzyme follows a sequential ordered mechanism with NADPH binding first. However, the "off constant" for NADP+ in the forward direction was 1 order of magnitude less than the kcat. Analysis of this anomaly by pre-steady state kinetics using stopped-flow fluorescence spectroscopy showed that this could be accounted for by isomerization of the enzyme-NADP+ complex and that the rate of isomerization is the rate-limiting step. The rate constant for this step was of the same order of magnitude as the kcat for the forward reaction. Fluorescence emission spectra of free and NADP(H)-bound enzyme suggested a conformational change upon binding of coenzyme. In the reverse direction (oxidation of glycerol) pre-steady state and steady state kinetic analyses were consistent with the rate-limiting step occurring before isomerization of the enzyme-NADPH complex. We conclude, therefore, that during the kinetic mechanism of the reduction of aldehydes by aldose reductase, a slow (kinetically detectable) conformational change in the enzyme occurs upon coenzyme binding. Since NADPH and NADP+ bind to the enzyme very tightly, this has implications for the targeting and binding of drugs that are aldose reductase inhibitors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6510-7
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Studies on pig muscle aldose reductase. Kinetic mechanism and evidence for a slow conformational change upon coenzyme binding.
pubmed:affiliation
Department of Biochemistry, Queen's University, Kingston, Ontario, Canada.
pubmed:publicationType
Journal Article