講演者 ： 橋本 洋佑 先生

講演者ご所属 ： 名古屋大学・環境医学研究所　脳機能分野

座長 ： 澤島　隆　（コスモ・バイオ株式会社）

日時 ： 8月31日(木)

会場 ： グランドプリンスホテル広島

協賛 ： コスモ・バイオ株式会社

要旨

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has been used to analyze a certain molecule of many biological samples in one or more mass-to-charge (m/z) values, providing the capability of detection for specific molecules in the original sample. The high sensitivity of detection in low-femtomole to attomole levels for highly purified proteins and peptides allows the study of organized biochemical processes, however, there are still a number of significant difficulties with MALDI-MS against crude biological samples such as serum, tissue homogenate, tissue extracts etc. MALDI-MS is hard to achieve high accuracy of reproducibility and quantification mostly due to variation of the tendencies to ionization of each molecule in the crude sample. Almost of biologically significant peptides are much less abundant than low molecular weight compounds such as amino acids, lipids, nucleotides etc., therefore, cumbersome isolation/purification processes are required. Recently, we have successfully indicated a new preparation method for analysis of biological materials with a thermal film-based MALDI MS system (Hot-melt MALDI-MS). This system enables to enhance ionization of peptidergic molecules (or to restrain ionization of much abundant low molecular weight molecules in biological mixture) on MALDI/TOF, so as to detect less abundant peptides. We could detect both monomer and dimer of amyloid beta peptides from a single-cell size dissected spot of frozen brain sections of Alzheimer model mouse. We also detected many peptidergic peaks from concentrated exosome fractions. This system will help to investigate the characteristics, compositions, origins and even biological significance of exosomes.

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