Intracellular degradation of C-peptides in molluscan neurons producing insulin-related hormones.
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.
de With
N D
ND
Graduate School of Neurosciences Amsterdam, Research Institute Neurosciences Vrije Universiteit, Faculty of Biology, The Netherlands. ndewith@bio.vu.nl
Li
K W
KW
Jiménez
C R
CR
Vonk
N
N
Dreisewerd
K
K
Hillenkamp
F
F
Karas
M
M
Geraerts
W P
WP
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
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