Linked Life Data

11897392

Source:http://linkedlifedata.com/resource/pubmed/id/11897392

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2002-3-18
pubmed:abstractText
Tachykinin-related peptides (TRP) are widely distributed in the CNS of insects, where they are likely to function as transmitters/modulators. Metabolic inactivation by membrane ecto-peptidases is one mechanism by which peptide signalling is terminated in the CNS. Using locustatachykinin-1 (LomTK-1, GPSGFYGVRamide) as a substrate and several selective peptidase inhibitors, we have compared the types of membrane associated peptidases present in the CNS of four insects, Locusta migratoria, Leucophaea maderae, Drosophila melanogaster and Lacanobia oleracea. A neprilysin (NEP)-like activity cleaving the G-F peptide bond was the major LomTK-1-degrading peptidase detected in locust brain membranes. NEP activity was also found in Leucophaea brain membranes, but the major peptidase was an angiotensin converting enzyme (ACE), cleaving the G-V peptide bond. Drosophila adult head and larval neuronal membranes cleaved the G-F and G-V peptide bonds. Phosphoramidon inhibited both these cleavages, but with markedly different potencies, indicating the presence in the fly brain of two NEP-like enzymes with different substrate and inhibitor specificity. In Drosophila, membrane ACE did not make a significant contribution to the cleavage of the G-V bond. In contrast, ACE was an important membrane peptidase in Lacanobia brain, whereas very little neuronal NEP could be detected. A dipeptidyl peptidase IV (DPP IV) that removed the GP dipeptide from the N-terminus of LomTK-1 was also found in Lacanobia neuronal membranes. This peptidase was a minor contributor to LomTK-1 metabolism by neuronal membranes from all four insect species. In Lacanobia, LomTK-1 was also a substrate for a deamidase that converted LomTK-1 to the free acid form. However, the deamidase was not an integral membrane protein and could be a lysosomal contaminant. It appears that insects from different orders can have different complements of neuropeptide-degrading enzymes. NEP, ACE and the deamidase are likely to be more efficient than the common DPP IV activity at terminating neuropeptide signalling since they cleave close to the C-terminus of the tachykinin, a region essential for maintaining biological activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0196-9781
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
725-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Inactivation of a tachykinin-related peptide: identification of four neuropeptide-degrading enzymes in neuronal membranes of insects from four different orders.
pubmed:affiliation
Molecular and Cellular Biosciences, Faculty of Biological Sciences, Miall Building, University of Leeds, LS2 9JT, Leeds, UK. r.e.isaac@leeds.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't