Carrette Odile, Burkhard Pierre R, Hughes Severine, Hochstrasser Denis F, Sanchez Jean-Charles
Biomedical Proteomics Research Group, Geneva University Hospital and Medical School, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland.
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.
胱抑素C是一种在人体体液中以生理浓度存在的低分子量半胱氨酸蛋白酶抑制剂，其在脑脊液（CSF）中的表达高于血浆。质谱分析表明，人脑脊液在-20℃储存3个月后，胱抑素C在R8和L9之间的肽键处被切割，失去了其N端的8个氨基酸，而在-80℃储存时则不会发生这种切割。无论潜在的神经学状态如何，在所研究的所有脑脊液样本中均发生了这种截短，这表明这是一种与储存相关的假象，而非该蛋白质的生理或病理加工过程。这些结果强调了在进行蛋白质组学研究之前，任何样本进行最佳分析前储存条件的重要性。
