[Purification and ligand-receptor analysis of insulin-related peptides from pedal ganglion of the mollusc Anodonta cygnea].
Six insulin-related peptides (IRPs) from pedal ganglions of the molluscs Anodonta cygnea have been isolated and purified by reverse-phase chromatography. Each peptide (designated as IRP8-IRP13) showed its own retention time on the HPLC column. The testing of IRPs in radioreceptor systems specific for insulin and insulin growth factor-I (IGF-I) showed their ability to bind to both types of receptors. The concentration of IRPs, producing a 50% inhibition of porcine 125I-insulin binding with rat liver plasma membrane receptors (IC50) for IRP 10, was 1167 nM, IRP11--833 nM, IRP13--1333 nm. IRP8, IRP9, IRP12 in the maximum concentration of 10(4) ng/ml displaced less than 50% of labeled hormone. All of the six peptides were capable of competing with human 125I-IGF-I for binding to receptors of a fraction of rat brain membranes. IRP8, IRP9 and IRP12 had close means equal to 1167 nM, 1500 nM, 1167 nM, respectively. Another group including IRP10, IRP11 and IRP13 showed a much higher activity (833, 83 and 500 nM, respectively). The results obtained from radioligand analysis revealed the predominance of IGF-I binding properties in all peptides of pedal ganglions. At the same time, apparent proximity of IRP's physico-chemical characteristics to porcine insulin, and also the revealed dose-dependent binding to both insulin and IGF-I receptors suggest a bifunctionality of mollusc peptides. The expression level of this bifunctionality may be associated with the molecular structure pecularities of individual isoforms.
Rusakov
Iu I
IuI
Kolychev
A P
AP
Shipilov
V N
VN
Bondareva
V M
VM
D000818:Animals; D001667:Binding, Competitive; D017952:Ganglia, Invertebrate / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008974:Mollusca / Q000378:metabolism*; D009479:Neuropeptides / Q000302:isolation & purification / Q000378:metabolism*; D011869:Radioligand Assay; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*
D008024:Ligands; D009479:Neuropeptides; C063879:insulin-related neuropeptide; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin