Eisai R&d Management Co., Ltd.

Yasushi Ishihama

Naoki Asakawa

Yoshiya Oda

Kaoru Murata

Eiichi Yamamoto

Tsuyoshi Tabata

The present inventor has established protein abundance index (PAI, &#x3c0;) to determine the protein contents in a protein mixture solution using nanoLC-MSMS data. Digested peptides were analyzed by nanoLC-MS/MS and the obtained results were applied to a Mascot protein identification algorism based on tandem mass spectra. For absolute quantitation, PAI was converted to exponentially modified PAI (EMPAI, m &#x3c0;), which is proportional to protein contents in the protein mixture. EMPAI was successfully applied to comprehensive protein expression analysis and performed a comparison study between gene and protein expression in an HCT116 human cancer cells. Accordingly, the present invention provides a method and a computer program for quantifying the protein contents based on the protein abundance index.

Absolute quantitation of protein contents based on exponentially modified protein abundance index by mass spectrometry

An object of the present invention is to quantitate with good accuracy, furthermore, quantitate absolutely, one or a plurality of biological molecules in a sample such as a tissue, a biological fluid, a cell, a cell organ or protein complex. By adding a metabolically isotope labeled biological molecule as an internal standard substance and measuring with a mass spectrometer, quantitating with good accuracy one or a plurality of target molecules in a sample has become possible. In addition, by performing waveform separation processing during mass analysis, a highly accurate quantitative analysis method of mass analysis is provided.

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Tsuruoka, Japan

Yasushi Ishihama