Detecting isomers using differential derivatization mass spectrometry
AssigneePerkinElmer Health Sciences, Inc.
InventorsBlas Cerda, Alex Cherkasskiy, Yijun Li
Life of this patent
Estimating the term…
Abstract
Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.
Claims25
A method of detecting one or more molecular isomers of one or more branched-chain amino acids in a sample, the method comprising:
- derivatizing one or more molecular isomers of one or more branched-chain amino acids in a sample, wherein the sample comprises one or more molecular isomers of one or more branched-chain amino acids and a first standard, the first standard being a branched-chain amino acid labeled with one or more heavy atoms;
- adding to the sample, after derivatization, a nonderivatized or derivatized branched-chain amino acid that is labeled with one or more heavy atoms as a second standard;
- evaluating the sample using tandem mass spectrometry;
- and
- detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample, thereby distinguishing between branched-chain amino acids that are molecular isomers in the sample.
A method of diagnosing a metabolic disorder, the method comprising:
- treating a sample from a subject under conditions in which one or more branched-chain amino acids in the sample are derivatized, wherein the sample comprises one or more molecular isomers of one or more branched-chain amino acids and a first standard, the first standard being a branched-chain amino acid labeled with one or more heavy atoms;
- adding to the sample, after derivatization, a nonderivatized or derivatized branched-chain amino acid that is labeled with one or more heavy atoms as a second standard;
- evaluating the sample using tandem mass spectrometry;
- and
- detecting signals indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample, thereby distinguishing between branched-chain amino acids that are molecular isomers in the sample,
- wherein an altered level of the one or more branched-chain amino acids in the sample relative to the level in one or more reference samples is an indication that the subject has, or is at risk of developing, a metabolic disorder characterized by altered levels of one or both of branched-chain amino acids and branched-chain ketoacids.
Dependencies are inferred from the claim text.