The Noguchi Institute

Shimadzu Corporation

Junko Amano

Koichi Tanaka

Ichiro Sugimoto

Kiyoko Hirano

The present invention provides a method for obtaining structural information conveniently and rapidly by generating a negative ion without adding an acidic substance to matrix, thereby improving sensitivity of measurement by a mass spectrometer, and by generating structural specific ions with high reproducibility, and a method for screening disease marker and a method for analyzing a sample containing a biomolecule. A method for mass spectrometry of a sugar chain comprising the steps of: preparing a sample containing a sugar chain; labeling the sugar chain with a labeling compound, to obtain a labeled sugar chain; and subjecting the labeled sugar chain to measurement of negative ions by using a MALDI mass spectrometer, thereby conducting analysis of the sugar chain. A method for screening disease marker comprising the steps of: (1) labeling the biomolecule X derived from a subject affected by a particular disease; subjecting the labeled biomolecule X' to measurement of negative ions by a MALDI mass spectrometer, (2) separately, labeling the biomolecule Y derived from a subject unaffected by the particular disease; subjecting the labeled biomolecule Y&#x2032; to measurement of negative ions by a MALDI mass spectrometer; and (3) comparing mass spectrum of the labeled biomolecule X&#x2032; obtained in (1) with mass spectrum of the labeled biomolecule Y&#x2032; obtained in (2) to find mass spectrum peaks which are mutually different, thereby ascertaining presence of structure involved in expression of the particular disease.

Method of negative-ion MALDI analysis of neutral labeled sugars and screening disease markers

The present invention provides a method for accurately discriminating between prostate carcinoma and benign prostatic hyperplasia based on a glycan structure of prostate specific antigen (PSA). The method of the present invention includes the steps of: purifying PSA from a sample derived from a subject; preparing a PSA derivative from the PSA; labeling the PSA derivative; and analyzing the labeled PSA derivative by the mass spectrometry method, in which the subject is identified as having prostate carcinoma when the ratio of the signal intensity of fucose-unbound glycan to the signal intensity of fucose-bound glycan in the labeled PSA derivative is greater than 1.0, and identified as having benign prostatic hyperplasia when the ratio is 1.0 or less.

Method for discriminating between prostatic cancer and benign prostatic hyperplasia

An object of the invention is to provide a method for enabling MS(n&#x3e;) analysis of a trace amount of a sample and easily and rapidly obtaining structural information by identifying a bonding position of the labeling compound in a molecule with the MS(n&#x3e;) analysis. According to the present invention, by labeling a particular moiety of the molecule in a stable manner, ions are easily generated and stabilized, thereby improving sensitivity of the MS. The amount of precursor ions generated in this manner is an amount enough to carry out the MS(n&#x3e;1) analysis and to generate structure-specific ions with high reproducibility. The structural information can be easily and rapidly obtained with high sensitivity.

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Tokyo, Japan

Junko Amano