Truncated cystatin C in cerebrospiral fluid: Technical [corrected] artefact or biological process?

Proteomics. 2005 Aug;5(12):3060-5. doi: 10.1002/pmic.200402039.


Cystatin C, a low molecular weight cysteine proteinase inhibitor present in human body fluids at physiological concentrations, is more expressed in cerebrospinal fluid (CSF) than in plasma. Mass spectrometric characterization showed that after 3 months of storage of human CSF at -20 degrees C, cystatin C was cleaved in the peptide bond between R8 and L9 and lost its eight N-termini amino acids, whereas this cleavage did not occur when stored at -80 degrees C. This truncation occurred in all CSF samples studied irrespective of the underlying neurological status, indicating a storage-related artefact rather than a physiological or pathological processing of the protein. These results stress the importance of optimal preanalytical storage conditions of any sample prior to proteomics studies.

MeSH terms

  • Artifacts
  • Cystatin C
  • Cystatins / cerebrospinal fluid*
  • Cystatins / chemistry*
  • Cysteine Proteinase Inhibitors / chemistry
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Mass Spectrometry / methods
  • Protein Array Analysis
  • Protein Structure, Tertiary
  • Proteins / chemistry
  • Proteomics / methods
  • Specimen Handling
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Temperature
  • Time Factors


  • CST3 protein, human
  • Cystatin C
  • Cystatins
  • Cysteine Proteinase Inhibitors
  • Proteins