Linked Life Data

15749695

Source:http://linkedlifedata.com/resource/pubmed/id/15749695

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2005-5-3
pubmed:abstractText
The active site glutamate (Glu(111)) and the active site histidine (His(112)) of insulin-degrading enzyme (IDE) were mutated. These mutant enzymes exhibit, in addition to a large decrease in catalytic activity, a change in the substrate-velocity response from a sigmoidal one seen with the native enzyme (Hill coefficient > 2), to a hyperbolic response. With 2-aminobenzoyl-GGFLRKHGQ-N-(2,4-dinitrophenyl)ethylenediamine as substrate, ATP and triphosphate increase the reaction rate of the wild type enzyme some 50-80-fold. This effect is dampened with glutamate mutants to no effect or less than a 3-fold increase in activity and changed to inhibition with the histidine mutants. Sedimentation equilibrium shows the IDE mutants exhibit a similar oligomeric distribution as the wild type enzyme, being predominantly monomeric, with triphosphate having little if any effect on the oligomeric state. Triphosphate did induce aggregation of many of the IDE mutants. Thus, the oligomeric state of IDE does not correlate with kinetic properties. The His(112) mutants were shown to bind zinc, but with a lower affinity than the wild type enzyme. The glutamate mutants displayed an altered cleavage profile for the peptide beta-endorphin. Wild type IDE cleaved beta-endorphin at Leu(17)-Phe(18) and Phe(18)-Lys(19), whereas the glutamate mutants cleaved at these sites, but in addition at Lys(19)-Asn(20) and at Met(5)-Thr(6). Thus, active site mutations of IDE are suggested to not only reduce catalytic activity but also cause local conformational changes that affect the allosteric properties of the enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17701-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Mutation of active site residues of insulin-degrading enzyme alters allosteric interactions.
pubmed:affiliation
Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural