Patent ID: 8298775

Claim:
A method for quantification of protein tyrosine phosphatase (PTP) comprising the following steps: 1) hydrolyzing a sample separated from a test subject; 2) adding a known amount of an isotope-substituted synthetic standard peptide to the hydrolyzed sample of step 1), wherein the synthetic standard peptide is selected from SEQ ID NOs:191, 220, 225, 236, 246, 202, 231, 186, 172, 176 and 238; 3) extracting wild type peptide and the isotope-substituted synthetic standard peptide from the hydrolyzed sample of step 2), followed by quantitative analysis; and 4) comparing the levels of the wild type peptide and the isotope-substituted synthetic standard peptide of step 3) to calculate a quantity of the wild type peptide expression.