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Prostate Specific Antigen IDBEST™ Example
We have demonstrated the IDBEST™ platform with the enrichment of prostate specific antigen (PSA) from IDBEST™-labeled human serum (Figure)1. This is the first time that any mass spectrometric proteomic method has seen PSA in serum samples. The peptide abundances were within 4% of the expected values and tandem MS was used to confirm the result as PSA by peptide identity.
In this IDBEST™ experiment, PSA was spiked at 100 ng/mL into healthy human serum, the sample was divided with half labeled with the heavy isotope lysine label and the other half labeled with the light isotope lysine label. The two labeled aliquots were mixed and affinity enriched from the mixture using a commercial anti-PSA mAb. The mass defect labeled PSA peptides were quantitatively deconvolved from the resulting mass spectrum. The identity of the first peptide was confirmed by tandem mass spectrometry (inset).
____________________ 1Schneider and Hall, Drug Discov. Today, 10:353-363 (2005).
