Peptide quantification by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry: investigations of the cyclotide kalata B1 in biological fluids

Michelle L Colgrave; Alun Jones; David J Craik

doi:10.1016/j.chroma.2005.07.094

Peptide quantification by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry: investigations of the cyclotide kalata B1 in biological fluids

J Chromatogr A. 2005 Oct 14;1091(1-2):187-93. doi: 10.1016/j.chroma.2005.07.094.

Authors

Michelle L Colgrave¹, Alun Jones, David J Craik

Affiliation

¹ Institutefor Molecular Bioscience, University of Queensland, ARC Special Research Centre for Functional and Applied Genomics, Brisbane 4072, Australia.

PMID: 16395810
DOI: 10.1016/j.chroma.2005.07.094

Abstract

A rapid method has been developed for the quantification of the prototypic cyclotide kalata B1 in water and plasma utilizing matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry. The unusual structure of the cyclotides means that they do not ionise as readily as linear peptides and as a result of their low ionisation efficiency, traditional LC/MS analyses were not able to reach the levels of detection required for the quantification of cyclotides in plasma for pharmacokinetic studies. MALDI-TOF-MS analysis showed linearity (R2 > 0.99) in the concentration range 0.05-10 microg/mL with a limit of detection of 0.05 microg/mL (9 fmol) in plasma. This paper highlights the applicability of MALDI-TOF mass spectrometry for the rapid and sensitive quantification of peptides in biological samples without the need for extensive extraction procedures.

MeSH terms

Amino Acid Sequence
Animals
Body Fluids / chemistry*
Calibration
Cyclotides / analysis*
Cyclotides / chemistry
Injections, Intravenous
Mass Spectrometry
Molecular Sequence Data
Protein Conformation
Rats
Rats, Sprague-Dawley
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*

Substances

Cyclotides
kalata B1