質量分析計によるタンパク質分子の多様性解析 : 肝細胞癌グルタミン合成酵素の翻訳後修飾

概要

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Mass spectrometric analysis of molecular diversity of human liver glutamine synthetase (GS) is described. An acidic isoform of GS, which is highly expressed in human well-differentiated hepatocellular carcinoma, and that caused by posttranslational modification of protein phosphorylation which was determined by post source decay (PSD) analysis using matrix assisted laser deionization/ionization-time of flight (MALDI-TOF) mass spectrometry. The peptide mass fingerprinting (PMF) of tryptic peptides of the GS isoform showed a loss of the signal of 899.5 Da corresponding a peptide of SASIRIPR and a gain of the signal of 1,059.5 Da which was submitted to PSD analysis. The PSD analysis showed the neutral loss by elimination of two phosphate groups which were supposed to be on serine residues of 899.5 Da peptide from serine 320 to arginine 327 in GS. The PMF followed by PSD analysis is useful for the determination of phosphorylation site(s) of proteins showing molecular heterogeneity.
日本質量分析学会の論文
2003-10-01