Title: Insect trypsin modulating oostatic factor (Neb-TMOF) and its analogs: Preliminary structure biological function relationship studies
Authors: Konopinska, D ×
Bartosz-Bechowski, H
Kuczer, Mariola
Rosinski, G
Janssen, Ine
De Loof, Arnold #
Issue Date: Oct-1998
Publisher: Kluwer academic publ
Series Title: Letters in peptide science vol:5 issue:5-6 pages:391-393
Abstract: Neb-TMOF, the trypsin modulating oostatic factor of gray fleshfly Neobellieria bullata, is a hexapeptide with the following sequence: H-Asn-Pro-Thr-Asn-Leu-His-OH. It has been isolated from vitellogenic ovaries in 1994. TMOF, the newly discovered insect peptide, inhibits trypsin biosynthesis in the gut, lowers yolk polypeptide concentration in the hemolymph and strongly inhibits ecdysone biosynthesis by larval ring glands. It is interesting that this short non-protected peptide contains in its molecule two Asn residues at positions 1 and 4 and His at its C-terminus. To obtain information about the role of the His-6 and Asn-4 residues we synthesised two series of Neb-TMOF analogs, modified: (1) in position 6 by D-His (I), His(Bzl) (II) and Phe(p-X) derivatives, where X = NH2 (III), NO2 (IV), OEt (V) and OH (VI) and (2) in position 4 by such amino acid residues as Ser (VII), Thr (VIII), Gly (IX), Asp (X), Glu (XI) and D-Asn (XII). The influence of these peptides on trypsin biosynthesis in N. bullata was determined in vivo. In preliminary investigations, we found that Neb-TMOF, [Phe(NH2)6], and [Phe(NO2)(6)]-Neb-TMOF inhibited trypsin biosynthesis, whereas [D-His)(6)]- and [D-His(Bzl)(6)]-Neb-TMOF were inactive. In further biological studies performed in vitro on heart of Tenebrio molitor we found that Neb-TMOF and [Phe(p-NH2)(6)]-Neb-TMOF showed weak cardioexcitatory activity, about 30% of the cardioexcitatory activity of proctolin, an insect neuromodulating peptide.
ISSN: 0929-5666
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Animal Physiology and Neurobiology Section - miscellaneous
Department of Biology - miscellaneous
× corresponding author
# (joint) last author

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