Thyroglobulin quantitation by mass spectroscopy
AssigneeQuest Diagnostics Investments Incorporated
InventorsYanni Zhang, Nigel J. Clarke, Richard E. Reitz
Life of this patent
Estimating the term…
Abstract
Provided are methods for determining the amount of thyroglobulin in a sample using various purification steps followed by mass spectrometry. The methods generally involve purifying thyroglobulin in a test sample, digesting thyroglobulin to form peptide T129, purifying peptide T129, ionizing peptide T129, detecting the amount of peptide T129 ion generated, and relating the amount of peptide T129 ion to the amount of thyroglobulin originally present in the sample.
Claims18
A method of determining the amount of thyroglobulin in a test sample, comprising:
- (a) digesting thyroglobulin (Tg) in the test sample;
- (b) enriching a digested Tg peptides comprising an amino acid sequence VIFDANAPVAVR (SEQ ID NO:1);
- (c) ionizing the Tg peptide and an isotopically labeled internal standard, wherein the internal standard comprises a synthetic winged peptide comprising an amino acid sequence VIFDANAPVAVR (SEQ ID NO:1) that is digested with thyroglobulin from the test sample;
- and
- (d) quantifying the amount of the Tg peptide ion from step (c) by mass spectrometry;
- wherein the amount of the Tg peptide ion detected in step (d) is related to the amount of thyroglobulin in said test sample.
A method of determining the amount of thyroglobulin in a test sample, comprising:
- (a) digesting thyroglobulin (Tg) in the test sample;
- (b) enriching a digested Tg peptide comprising an amino acid sequence VIFDANAPVAVR (SEQ ID NO:1);
- (c) ionizing the Tg peptide and an isotopically labeled internal standard to generate precursor ions detectable by tandem mass spectrometry, wherein the internal standard comprises a synthetic winged peptide comprising an amino acid sequence VIFDANAPVAVR (SEQ ID NO:1) that is digested with thyroglobulin from the test sample;
- wherein said precursor ion of the Tg peptide has a mass/charge ratio of 636.4±0.5;
- (d) fragmenting said precursor ions in said mass spectrometric instrument to generate one or more fragment ions detectable by mass spectrometry, wherein one or more of said fragment ions of the Tg peptide comprise ions having a mass/charge ratio of 797.4±0.5;
- 912.4±0.5, or 1059.5±0.5;
- and
- (e) quantifying the amount of said precursor ions of step (c), one or more of said fragment ions of step (d), or both, by mass spectrometry;
- wherein the amount of ion(s) detected in step (e), is related to the amount of said thyroglobulin in said test sample.
Dependencies are inferred from the claim text.