The binding of an amphipathic ␣-helical peptide to small unilamellar lipid vesicles has been examined using chemical derivitization and mass spectrometry. The peptide is derived from the sequence of human apolipoprotein C-II (apoC-II), the protein activator of lipoprotein lipase (LpL). ApoC-II 19 -3
Characterization of binding of the annelidan myoactive peptides, GGNG peptides, to tissues of the earthworm,Eisenia foetida
✍ Scribed by Niida, T.; Nagahama, T.; Oumi, T.; Ukena, K.; Morishita, F.; Furukawa, Y.; Matsushima, O.; Tsutsui, K.; Ohtani, M.; Muneoka, Y.; Fujita, T.; Kawano, T.; Minakata, H.; Nomoto, K.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 205 KB
- Volume
- 279
- Category
- Article
- ISSN
- 0022-104X
No coin nor oath required. For personal study only.
✦ Synopsis
The GGNG peptides are myoactive peptides which we have isolated from several species of annelids. Two types of peptides have been isolated as GGNG peptides: earthworm excitatory peptides (EEP) and leech excitatory peptide (LEP). The EEP and LEP are highly homologous with each other but act specifically on earthworms and leeches, respectively. To approach the mechanism of the specific action, we attempted to characterize the receptors for EEP in the earthworm Eisenia foetida, from which EEP have been isolated, by a radioreceptor assay. To prepare a radiolabeled ligand, we first coupled EEP to Bolton-Hunter reagent and then labeled it with 125 I ([ 125 I] BH-EEP). Binding of the [ 125 I] BH-EEP to the membrane preparation of the earthworm tissue (crop-gizzard) was reversible, saturable, and specific with a Kd of 4.9 ± 1.2 nM and a B max of 15.9 ± 2.0 fmol/mg wet tissue. For the earthworm membrane preparation, EEP showed a much greater potency than LEP in displacing [ 125 I] BH-EEP, suggesting that the earthworm tissues contain EEP-specific receptors. This result would account for the specific biological activity of EEP and LEP on the earthworm and leech tissues, respectively. The binding capacity was high in the anterior part of digestive tract including the esophagus, crop and gizzard, and the nephridia. From these results, together with the observed myotropic activity of EEP on gut tissues, it is assumed that EEP is physiologically involved in regulation of the gut motility in the earthworm
📜 SIMILAR VOLUMES
Affinity coelectrophoresis (ACE) is a technique for characterizing ligand/nucleic acid binding interactions under equilibrium conditions. It is used here to characterize the protamine clupeine \(\mathrm{Z}\) binding to several DNA fragments in order to define the use and limitations of ACE for ligan
## Abstract Two‐dimensional ^1^H NMR experiments that achieve band‐selective, homonuclear decoupling in both the indirectly detected F1 and directly detected F2 dimensions were used to assign the highly overlapped ^1^H NMR spectrum of the peptide Ac‐SRGKARVRAKVKDQTK‐NH~2~, both free in solution and