摘要:
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.
摘要:
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.
摘要:
There are provided a peptide consisting of an amino acid sequence for simultaneously quantifying absolute amounts of metabolizing enzyme proteins in a biological sample at high sensitivity and a method for using the same. A peptide which can be detected at high sensitivity with a mass spectrometer that enables highly sensitive simultaneous quantification of metabolizing enzymes, intracellular proteins, is selected, and the amino acid sequence thereof is identified. Using a stable-isotope-labeled peptide having the same amino acid sequence as the amino acid sequence of this peptide to be quantified, a mass spectrometry by LC-MS/MS is performed at predetermined concentration levels of the stable-isotope-labeled peptide to create a calibration curve. The stable-isotope-labeled peptide is added to a peptide fragment obtained by fragmenting metabolizing enzyme proteins to be quantified in a sample with trypsin, amass spectrometry by LC-MS/MS is performed to calculate amass spectrum area ratio of the metabolizing enzyme protein peptides to be quantified and the stable-isotope-labeled peptide, and a quantitative value is obtained from the area ratio using the calibration curve.
摘要:
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.
摘要:
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.
摘要:
New peptides represented by the following general formula (wherein X is OH or NH2, R is an amino acid residue selected from Arg, His, Lys, Methyl-Arg or Methyl-Tyr, n is an integer of 1-4, and in the case that n is 2-4, R may be identical with or different from each other) and an anti-dementia drug which contains one or more of these new peptides and has a high blood brain barrier (BBB) permeability and furthermore is low in a side effect.
摘要:
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 β, and Angiopoietin-1. In addition, the immortalized vascular pericyte line has ability to deposit calcium on matrix by dense culture.
摘要:
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.
摘要翻译:提供了一种通过以简单,快速和准确的方式通过质谱法使用稳定同位素标记肽作为探针来定量存在的质膜蛋白质的方法。 将质膜蛋白质片段化以制备通过LC / MS / MS鉴定的寡肽片段。 如果通过用蛋白酶片段化获得肽,则该肽对靶分子是特异性的,并且如果该肽基于疏水性氨基酸含量,序列条件的选择性标准具有高的总分值,则选择用于定量的主题肽, 氨基酸残基数,特定氨基酸序列条件等。根据这些标准,选择可通过ESI方法离子化的主题肽片段。 通过使用目标肽和稳定同位素标记的肽,通过质谱法精确定量质膜蛋白质。