کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2202276 | 1100084 | 2006 | 7 صفحه PDF | دانلود رایگان |

A key factor in the characterization of peptide transmitters used in neuronal signaling is the correct elucidation of post-translational modifications, especially as they are often required to confer biological activity. A rare carboxylation modification is described on the D-peptide from the insulin prohormone in the sea slug, Aplysia californica. Using liquid chromatography purification coupled with electrospray ionization and nanoelectrospray ionization-ion trap-mass spectrometry (ESI- and nanoESI-MS), the presence of this D-peptide within Aplysia insulin (AI)-producing neurons is confirmed. Further detailed mass spectrometric analyses demonstrate that the Aplysia insulin D-peptide is carboxylated on the single glutamate residue within the sequence. This γ-carboxy D-peptide, along with other identified AI-related peptides, is secreted from the central nervous system in response to ionophore stimulation, thus suggesting a signaling role within the nervous system. Although carboxylated peptides have been described previously, the Aplysia γ-carboxy D-peptide appears to be the first reported carboxylated neuropeptide.
Journal: Neurochemistry International - Volume 49, Issue 3, August 2006, Pages 223–229