Intracellular degradation of C-peptides in molluscan neurons producing insulin-related hormones

Peptides. 1997;18(6):765-70. doi: 10.1016/s0196-9781(97)00020-x.


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.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chromatography, High Pressure Liquid
  • Invertebrate Hormones / metabolism*
  • Lymnaea
  • Molecular Sequence Data
  • Neurons / metabolism*
  • Neuropeptides / metabolism*
  • Peptide Fragments / metabolism
  • Protein Precursors / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Invertebrate Hormones
  • Neuropeptides
  • Peptide Fragments
  • Protein Precursors
  • insulin-related neuropeptide
  • insulin-related peptide I
  • insulin-related peptide III, Lymnaea