Linked Life Data

18822395

Source:http://linkedlifedata.com/resource/pubmed/id/18822395

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2008-11-5
pubmed:abstractText
The aim of this study was to investigate the mechanism by which tripeptidyl-peptidase II (TPP II) can specifically release tripeptides from the free N-terminus of an oligopeptide. The subtilisin-like N-terminal part of TPP II was modelled using subtilisin as template. Two glutamate residues (Glu-305 and Glu-331) appeared to be positioned so as to interact with the positively charged N-terminus of the substrate. In order to test this potential interaction, both residues were replaced by glutamine and lysine. The catalytic efficiency was reduced 400-fold for the E331Q variant and 20000-fold for the E331K variant, compared with the wild-type (wt). A substantial part of this reduction was due to decreased substrate affinity, since the K(M) for both mutants was at least two orders of magnitude greater than for the wt. This decrease was linked specifically to interaction with the free N-terminal amino group, based on inhibition studies. Glu-305 appears to be essential for enzymatic activity, but the extremely low activity of the E305Q variant prevented an investigation of the involvement of Glu-305 in substrate binding. The present work is, to our knowledge, the first report to investigate a mechanism for a tripeptidyl-peptidase activity through site-directed mutagenesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:volume
1784
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1899-907
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Investigation of a role for Glu-331 and Glu-305 in substrate binding of tripeptidyl-peptidase II.
pubmed:affiliation
Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't