title: Intracellular degradation of C-peptides in molluscan neurons producing insulin-related hormones.
abstract: Single Light Green Cells (LGC) of Lymnaea stagnalis, expressing four genes encoding insulin-related peptides (MIPs) and C-peptides, and sections from the median lip nerve (MLN) were subjected to MALDI-MS. Mass spectra of LGCs and MLNs were almost identical. Masses corresponding to those of the MIPs and some C alpha-peptides could be distinguished. ProMIP III C alpha-peptide and C beta-peptides were not found. The spectra showed additional masses matching those of carboxyterminally truncated C alpha-peptides. Peptides with similar masses were isolated from MLN extracts by HPLC, using electrospray-MS screening. Amino acid sequence analysis revealed intact proMIP I, II and V C alpha-peptides and I, II C alpha-peptide 1-24, 1-22 and 1-15.
authors.affiliation: Graduate School of Neurosciences Amsterdam, Research Institute Neurosciences Vrije Universiteit, Faculty of Biology, The Netherlands. ndewith@bio.vu.nl
authors.forename: N D
authors.initials: ND
authors.lastname: de With
authors.forename: K W
authors.initials: KW
authors.lastname: Li
authors.forename: C R
authors.initials: CR
authors.lastname: Jiménez
authors.forename: N
authors.initials: N
authors.lastname: Vonk
authors.forename: K
authors.initials: K
authors.lastname: Dreisewerd
authors.forename: F
authors.initials: F
authors.lastname: Hillenkamp
authors.forename: M
authors.initials: M
authors.lastname: Karas
authors.forename: W P
authors.initials: WP
authors.lastname: Geraerts
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007447:Invertebrate Hormones / Q000378:metabolism*; D008195:Lymnaea; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D007447:Invertebrate Hormones; D009479:Neuropeptides; D010446:Peptide Fragments; D011498:Protein Precursors; C063879:insulin-related neuropeptide; C110324:insulin-related peptide I; C084389:insulin-related peptide III, Lymnaea