Mass spectrometry and characterization of Aedes aegypti trypsin modulating oostatic factor (TMOF) and its analogs.

摘要: Trypsin modulating oostatic factor (TMOF), a decapeptide that directly inhibits the biosynthesis of trypsin- and chymotrypsin-like enzymes in epithelial cells mosquito midgut indirectly vitellogenesis anautogenous females, has been sequenced by Fourier transform mass spectrometry analysis. The peptide primary amino acid sequence NH2-Tyr-Asp-Pro-Ala-(Pro)6-COOH probably exhibits left-handed helical conformation as was shown computer stereoview simulation. is metabolized very rapidly (half-life 1.6 h) intact mosquitoes when injected after blood meal. Inhibition trypsin followed ligated abdomens, which synthesize but do not metabolise TMOF. At concentrations 3 x 10(-9) M 6.8 10(-6) M, TMOF inhibited 50 90% trypsin-like enzyme biosynthesis, respectively. Several analogs varying chain lengths were synthesized evaluated for biological activity using dose-response curves. Switching positions Tyr Asp at N-terminus reduced hormone, indicating important activity. Removal two to five prolines C-terminus also activity, both N- C-termini are important. Synthesis isozyme several insect species [1,3-3H]diisopropyl-fluorophosphate (DFP) presence tosylamide-2-phenylethyl chloromethyl ketone. Marked reduction [1,3-3H]diisopropyl-phosphoryl-trypsin-like derivatives noted treatment, assessed polyacrylamide gel electrophoresis. These results indicate other insects may be regulated sequence-related TMOFs.