30 results about "Selected reaction monitoring" patented technology

The present invention is directed to a simple method for absolute quantification of plasma vitellogenin from two or more different fish species such as Rainbow trout and Atlantic salmon, or Atlantic cod and haddock. In the case of Rainbow trout and Atlantic salmon, plasma samples obtained from control and β-estradiol induced fish were digested with trypsin. A characteristic ‘signature peptide’ was selected and analyzed by high performance liquid chromatography coupled to an electrospray quadrupole-time-of-flight tandem mass spectrometer, using a deuterated homologue peptide as an internal standard. The hybrid tandem mass spectrometer was operated in a ‘pseudo’ selected reaction monitoring mode by which three diagnostic product ions were monitored for identification and quantification purposes. The reproducibility (coefficient of variation ˜5%) and sensitivity (limit of quantification of 0.009 mg / mL) achieved by this simple assay allow it to be considered as an alternative to immunological assays. In the case of Atlantic cod and haddock, the amino acid sequence of the vitellogenin protein has not yet been determined, but, the Atlantic cod vitellogenin has been characterized using a ‘bottom-up’ mass spectrometric approach. Vitellogenin synthesis was induced ‘in vivo’ with β-Estradiol, and subjected to trypsin digestion for characterization by matrix-assisted laser desorption / ionization-Quadrupole-Time-of-flight tandem mass spectrometry. A peptide mass fingerprint was obtained and ‘de novo’ sequencing of the most abundant tryptic peptides was performed by low energy collision induced dissociation-tandem mass spectrometry. Thus, the sequences of various tryptic peptides have been elucidated. It has also been determined that Atlantic cod vitellogenin shares a series of common peptides with the two different known vitellogenin sequences of Haddock, a closely related species. There are also disclosed novel isolated signature peptides, namely Thr-Tyr-Phe-Ala-Gly-Ala-Ala-Ala-Asp-Val-Leu-Glu-Val-Gly-Val-Arg, Asp Leu Gly Leu Ala Tyr Thr Glu Lys, Phe Phe Gly Gln Glu Ile Ala Asn Ile Asp Lys, Glu Ile Val Leu Leu Gly Tyr Gly Thr Met Ile Ser Lys and Tyr Glu Ser Phe Ala Val Ala Arg.

Antibody-free processes are disclosed that provide accurate quantification of a wide variety of low-abundance target analytes in complex samples. The processes can employ high-pressure, high-resolution chromatographic separations for analyte enrichment. Intelligent selection of target fractions may be performed via on-line Selected Reaction Monitoring (SRM) or off-line rapid screening of internal standards. Quantification may be performed on individual or multiplexed fractions. Applications include analyses of, e.g., very low abundance proteins or candidate biomarkers in plasma, cell, or tissue samples without the need for affinity-specific reagents.

Systems and methods are provided for species detection using mass spectrometry. In various embodiments, a multiple reaction monitoring (MRM) experiment is performed on a sample targeting one or more peptide transitions that are unique to one or more species using a tandem mass spectrometer. One or more measured product ion spectra are received from the tandem mass spectrometer using the processor. The one or more measured product ion spectra are compared to product ions of the one or more peptide transitions that are unique to one or more species using the processor. One or more species of the sample are detected by reporting product ions of the one or more peptide transitions that are unique to one or more species that match the one or more measured product ion spectra using the processor.

The current disclosure provides for specific peptides, and derived ionization characteristics of the peptides, from the KRT5, KRT7, NapsinA, TTF1, TP63, and / or MUC1 proteins that are particularly advantageous for quantifying the KRT5, KRT7, NapsinA, TTF1, TP63, and / or MUC1 proteins directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry, or what can also be termed as Multiple Reaction Monitoring (MRM) mass spectrometry. Such biological samples are chemically preserved and fixed wherein said biological sample is selected from tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and or paraffin embedded. A protein sample is prepared from said biological sample using the Liquid Tissue™ reagents and protocol and the KRT5, KRT7, NapsinA, TTF1, TP63, and / or MUC1 proteins are quantitated in the Liquid Tissue™ sample by the method of SRM / MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides described. These peptides can be quantitated if they reside in a modified or an unmodified form. An example of a modified form of a KRT5, KRT7, NapsinA, TTF1, TP63, and MUC1 fragment peptide is phosphorylation of a tyrosine, threonine, serine, and / or other amino acid residues within the peptide sequence.

Systems and methods are provided for species detection using mass spectrometry. In various embodiments, a multiple reaction monitoring (MRM) experiment is performed on a sample targeting one or more peptide transitions that are unique to one or more species using a tandem mass spectrometer. One or more measured product ion spectra are received from the tandem mass spectrometer using the processor. The one or more measured product ion spectra are compared to product ions of the one or more peptide transitions that are unique to one or more species using the processor. One or more species of the sample are detected by reporting product ions of the one or more peptide transitions that are unique to one or more species that match the one or more measured product ion spectra using the processor.

A method for operating a mass spectrometer so as to detect or quantify analytes, comprises: (a) identifying a selected-reaction-monitoring (SRM) transition to be used for each respective analyte; (b) determining a time duration required for a fragmentation reaction corresponding to each identified transition to proceed to a threshold percentage of completion; and (c) for each analyte, performing the steps of (i) isolating ions corresponding to a precursor-ion mass-to-charge (m / z) ratio of the respective transition; (ii) fragmenting the respective isolated ions in one of two fragmentation cells or fragmentation cell portions; and (ii) mass analyzing for fragment ions corresponding to a product-ion m / z ratio of the respective transition, wherein, for each analyte, the fragmentation cell or fragmentation cell portion that is used for fragmenting the isolated ions is determined from the time duration determined for the respective analyte.

The current disclosure provides methods for detecting and quantitating the 6-O-methylguanine-DNA methyltransferase protein (MGMT) directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring / Multiple Reaction Monitoring (SRM / MRM) mass spectrometry. Such biological samples are chemically preserved and fixed with formaldehyde containing agents / fixatives and may include formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and / or paraffin embedded. A protein sample is prepared from the biological sample and the MGMT protein is quantitated in the sample using SRM / MRM mass spectrometry by quantitating one or more fragment peptides.

A collision cell has a plurality of rod electrodes arranged in opposed pairs around an axial centerline and a plurality of drag vanes arranged in the interstitial spaces between the rod electrodes. Operating the collision cell includes, applying a rod offset voltage to the rod electrodes, and varying an offset voltage applied to the drag vanes to identify a vane offset voltage with a maximum intensity for the transition. The method further includes varying a drag field by adjusting the voltages applied to drag vane terminals in opposite directions to identify a drag field value with a cross talk below a cross talk threshold, varying the vane offset voltage by adjusting the voltages applied to the drag vane terminals to maximize the intensity of the transition while preserving the drag field, and operating the collision cell at the vane offset voltage and drag field to monitor the transition.

The current disclosure provides methods for detecting and quantitating the 6-O-methylguanine-DNA methyltransferase protein (MGMT) directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring / Multiple Reaction Monitoring (SRM / MRM) mass spectrometry. Such biological samples are chemically preserved and fixed with formaldehyde containing agents / fixatives and may include formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and / or paraffin embedded. A protein sample is prepared from the biological sample and the MGMT protein is quantitated in the sample using SRM / MRM mass spectrometry by quantitating one or more fragment peptides.

Methods are provided for quantifying the Androgen receptor protein (AR) protein directly in biological samples that have been fixed in formalin, using Selected Reaction Monitoring (SRM) / Multiple Reaction Monitoring (MRM) mass spectrometry. The biological samples are chemically preserved and fixed and can be, for example, tissues treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks. A protein sample is prepared from said biological sample using, for example, the Liquid Tissue protocol and the AR protein is quantitated in the Liquid Tissue sample by the method of SRM / MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides described.

The current disclosure provides for a specific peptide, and derived ionization characteristics of a peptide from the tubulin beta-3 chain protein (TUBB3) that is particularly advantageous for quantifying the TUBB3 protein directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry. A protein sample is prepared from a biological sample using the Liquid Tissue reagents and protocol and the TUBB3 protein is quantitated by SRM / MRM mass spectrometry analysis of the sample, where the specific peptide is quantitated. Methods of treatment are provided in which the measured level of TUBB3 in a patient tumor sample is compared with a reference level and the patient is treated with a taxane-based treatment regimen when the measured TUBB3 level is lower than the reference level. A suitable reference level is, for example, about 700 amol / μg tissue.

Antibody-free processes are disclosed that provide accurate quantification of a wide variety of low-abundance target analytes in complex samples. The processes can employ high-pressure, high-resolution chromatographic separations for analyte enrichment. Intelligent selection of target fractions may be performed via on-line Selected Reaction Monitoring (SRM) or off-line rapid screening of internal standards. Quantification may be performed on individual or multiplexed fractions. Applications include analyses of, e.g., very low abundance proteins or candidate biomarkers in plasma, cell, or tissue samples without the need for affinity-specific reagents.

The current disclosure provides for a specific peptide, and derived ionization characteristics of a peptide from the tubulin beta-3 chain protein (TUBB3) that is particularly advantageous for quantifying the TUBB3 protein directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry. A protein sample is prepared from a biological sample using the Liquid Tissue reagents and protocol and the TUBB3 protein is quantitated by SRM / MRM mass spectrometry analysis of the sample, where the specific peptide is quantitated. Methods oftreatment are provided in which the measured level of TUBB3 in a patient tumor sample is compared with a reference level and the patient is treated with a taxane-based treatment regimen when the measured TUBB3 level is lower than the reference level. A suitable reference level is, for example, about 700 amol / [mu]g tissue.

The current disclosure provides for specific peptides, and derived ionization characteristics of the peptides, from the tyrosine-protein kinase receptor UFO protein (AXL) that are particularly advantageous for quantifying the AXL protein directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry, or what can also be termed as Multiple Reaction Monitoring (MRM) mass spectrometry. Such biological samples are chemically preserved and fixed wherein said biological sample is selected from tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and or paraffin embedded. A protein sample is prepared from said biological sample using the Liquid Tissue reagents and protocol and the AXL protein is quantitated in the Liquid Tissue sample by the method of SRM / MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides described. These peptides can be quantitated if they reside in a modified or an unmodified form. An example of a modified form of an AXL peptide is phosphorylation of a tyrosine, threonine, serine, and / or other amino acid residues within the peptide sequence.

The current disclosure provides methods for quantifying the MSLN protein directly in biological samples, including samples that have been fixed in formalin by Selected Reaction Monitoring / Multiple Reaction Monitoring (SRM / MRM) mass spectrometry. Samples that can be assayed include tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and or paraffin embedded. Methods to prepare a protein sample from such a biological sample are provided and MSLN protein is quantitated by SRM / MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides described.

The current disclosure provides for specific peptides, and derived ionization characteristics of the peptides, from the tyrosine-protein kinase receptor UFO protein (AXL) that are particularly advantageous for quantifying the AXL protein directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry, or what can also be termed as Multiple Reaction Monitoring (MRM) mass spectrometry. Such biological samples are chemically preserved and fixed wherein said biological sample is selected from tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and or paraffin embedded. A protein sample is prepared from said biological sample using the Liquid Tissue reagents and protocol and the AXL protein is quantitated in the Liquid Tissue sample by the method of SRM / MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides described. These peptides can be quantitated if they reside in a modified or an unmodified form. An example of a modified form of an AXL peptide is phosphorylation of a tyrosine, threonine, serine, and / or other amino acid residues within the peptide sequence.

Methods are provided for quantifying the fibroblast growth factor receptor 2 protein (FGFR2) directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) / Multiple Reaction Monitoring (MRM) mass spectrometry. The biological sample may be selected from tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells. A protein sample is prepared from the biological sample and the FGFR2 protein is quantitated in the sample using the method of SRM / MRM mass spectrometry by quantitating in the protein sample at least one fragment peptide derived from FGFR2.

Methods are provided for detecting and quantifying the Mesothelin protein (MSLN) in biological samples that have been fixed in formalin using Selected Reaction Monitoring (SRM) / Multiple Reaction Monitoring (MRM) mass spectrometry. The biological sample may be, for example, tissues and cells treated with formaldehyde containing agents / fixatives including formalin-fixed tissue / cells, formalin-fixed / paraffin embedded (FFPE) tissue / cells, FFPE tissue blocks and cells from those blocks, and tissue culture cells that have been formalin fixed and or paraffin embedded. A protein sample is prepared from the biological sample and the MSLN protein is quantitated by SRM / MRM mass spectrometry by quantitating one or more MSLN fragment peptides in the protein sample.

The invention relates to a method for the determination of an MRM or SRM assay for a protein of interest, a peptide of interest, or a group of proteins / peptides of interest or a whole proteome. It essentially includes the following steps: (1) a list of proteins of interest is selected and for each member at least one or a list of candidate proteotypic peptides is derived (2) this at least one peptide is synthesized / generated essentially without subsequent purification; (3) this at least one unpurified peptide is analyzed by selected reaction monitoring (SRM) preferably coupled to liquid chromatography (LC-SRM) or analogous techniques; (4) validation and / or optimisation of the corresponding assay of the at least one peptide with determination of the SRM coordinates for a peptide / protein of interest and / or of a regulator of interest is achieved. A protein sample of interest is enzymatically digested and can then be analyzed in SRM mode or time-constrained SRM mode, using elution times to trigger acquisition of the set of selected SRM traces, thus drastically increasing the throughput. The analysis allows to detect and quantify the set of peptides / proteins of interest. The method additionally relates to a tagging strategy to achieve absolute quantification of the peptides / proteins of interest at low-budget and high-throughput.