Tohoku University

Japan Science and Technology Agency

Tetsuya Terasaki

Sumio Ohtsuki

Junichi Kamiie

Masuo Obinata

Sumio Otsuki

Hisashi Iizasa

Kenji Hattori

Emi Nakashima

Kenji Room 202 Shenesuhauze Hattori

Disclosed is an evaluation peptide for evaluating the efficiency of a pretreatment in the quantification of a protein using a mass spectrometer, having high reliability and high general versatility. Also disclosed is an artificial standard protein comprising the evaluation peptide. Further disclosed is a method for quantifying a protein utilizing the artificial standard protein. Specifically disclosed is a method for selecting a peptide which consists of an amino acid sequence not agreeing with that in a naturally occurring protein and a variant thereof and capable of being detected by mass spectrometry and which has an amino acid that can be recognized by a protein-digesting enzyme, and using the peptide as an evaluation peptide for use in the quantification of a protein by a mass spectrometer.

Evaluation peptide for use in quantification of protein using mass spectrometer, artificial standard protein, and method for quantifying protein

An object of the present invention is to provide a method for producing a stable isotope-labeled target peptide fragment in mass spectrometry, which achieves inexpensive and convenient production. As a solution to attain the object, the stable isotope-labeled target peptide fragment in mass spectrometry is produced using a method comprising the steps of: expressing a DNA conjugate in a system having a stable isotope-labeled amino acid to thereby prepare a stable isotope-labeled protein, wherein the DNA conjugate comprises: a tandemly linked DNA in which two or more DNAs encoding one or more types of target peptide fragments are linked in tandem; and a DNA encoding a peptide fragment for concentration measurement; subjecting the stable isotope-labeled protein to fragmentation treatment with trypsin to prepare a stable isotope-labeled peptide fragment for concentration measurement and stable isotope-labeled target peptide fragments; quantifying the stable isotope-labeled peptide fragment for concentration measurement using a liquid chromatograph-tandem mass spectrometer (LC/MS/MS); and calculating the concentration of the stable isotope-labeled target peptide fragment of each type from the quantification value of the stable isotope-labeled peptide fragment for concentration measurement.

Method for fabricating stable-isotope-labeled target peptide fragment in mass spectrometry

A method is provided for quantifying a plasma membrane protein present by using a stable-isotope labeled peptide as a probe by mass spectrometry in a simple, quick and accurate manner. A plasma membrane protein is fragmented to prepare an oligopeptide fragment, identified by LC/MS/MS. A subject peptide for quantification is selected if the peptide is obtained by fragmenting with a protease, the peptide is specific to a target molecule, and if the peptide has a high total score value based on selective criteria for hydrophobic amino acids content, sequence conditions, number of amino acid residues, specific amino acid sequence conditions, etc. According to these criteria, a subject peptide fragment that can be ionized by ESI method is selected. By using the subject peptide for and a stable-isotope labeled peptide, the plasma membrane protein is quantified accurately by mass spectrometry.

Method of quantifying membrane protein by mass spectrometry using peptide selection criteria

To provide an immortalized capillary pericyte line which maintains the original function/property of the cell line-deriving tissue, its establishment method, and the screening method for useful substance using the immortalized capillary pericyte line. Cerebral tissue of a transgenic rat carrying the large T antigen gene of SV40 thermo-sensitive mutant line tsA58 is homogenized and the resultant brain capillaries are treated with protease, thus obtained brain capillary cells are subcultured to establish an immortalized cell that expresses SV40 thermo-sensitive large T antigen, PDGF receptor &#x3b2;, and Angiopoietin-1. In addition, the immortalized vascular pericyte line has ability to deposit calcium on matrix by dense culture.

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Sendai, Japan

Tetsuya Terasaki