Chromatographic separation and mass spectrometric identification of positional isomers of polyethylene glycol-modified growth hormone-releasing factor (1-29)

J Chromatogr A. 2004 Dec 17;1061(1):45-9. doi: 10.1016/j.chroma.2004.10.062.

Abstract

A one-step chromatographic method capable of separating all isomers of polyethylene glycol (PEG)-growth hormone-releasing factor (GRF) (1-29) conjugates was developed. The unmodified GRF (1-29) and seven different isomers of PEG-GRF (1-29) conjugates were separated by using a simple reversed-phase HPLC method depending on the differences of hydrophobicity due to the number and site of PEG attachment. The PEGylation sites of all isomers of PEG-GRF (1-29) conjugates were identified by determining the molecular masses of the Lys-C digested fragments with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This study is a first report for the separation of all PEG-conjugate isomers and would be useful for further studies to find the promising conjugate by evaluating biological activity and stability of each isomer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chromatography, High Pressure Liquid / methods*
  • Growth Hormone-Releasing Hormone / chemistry*
  • Isomerism
  • Molecular Sequence Data
  • Peptide Fragments / chemistry*
  • Polyethylene Glycols / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*

Substances

  • Peptide Fragments
  • Polyethylene Glycols
  • Growth Hormone-Releasing Hormone
  • somatotropin releasing hormone (1-29)