Identification and localization of the fatty acid modification in ghrelin by electron capture dissociation.

Published

Journal Article

Electron capture dissociation (ECD) has been demonstrated to be an effective fragmentation technique for characterizing the site and structure of the fatty acid modification in ghrelin, a 28-residue growth-hormone-releasing peptide that has an unusual ester-linked n-octanoyl (C8:0) modification at Ser-3. ECD cleaves 21 of 23 possible backbone amine bonds, with the product ions (c and z* ions) covering a greater amino acid sequence than those obtained by collisionally activated dissociation (CAD). Consistent with the ECD nonergodic mechanism, the ester-linked octanoyl group is retained on all backbone cleavage product ions, allowing for direct localization of this labile modification. In addition, ECD also induces the ester bond cleavage to cause the loss of octanoic acid from the ghrelin molecular ion; the elimination process is initiated by the capture of an electron at the protonated ester group, which is followed by the radical-site-initiated reaction known as alpha-cleavage. The chemical composition of the attached fatty acid can be directly obtained from the accurate Fourier transform ion cyclotron resonance (FTICR) mass measurement of the ester bond cleavage product ions.

Full Text

Duke Authors

Cited Authors

  • Guan, Z

Published Date

  • December 2002

Published In

Volume / Issue

  • 13 / 12

Start / End Page

  • 1443 - 1447

PubMed ID

  • 12484464

Pubmed Central ID

  • 12484464

Electronic International Standard Serial Number (EISSN)

  • 1879-1123

International Standard Serial Number (ISSN)

  • 1044-0305

Digital Object Identifier (DOI)

  • 10.1016/s1044-0305(02)00707-9

Language

  • eng