Ultrasensitive quantitative LC-MS/MS of an inhibitor of apoptosis protein's antagonist in plasma using protein target affinity extraction
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Updated: Mar 26, 2026
A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis
Published on: January 24, 2017
Lorell N Discenza1, Georgia Cornelius1, Jinping Gan2
1Bioanalytical Research, Bristol-Myers Squibb Company, Route 206 & Province Line Road, Princeton, NJ 08543, USA.
Background:
A target protein-based affinity extraction LC-MS/MS method was developed to enable plasma level determination following ultralow dosing (0.1-3 µg/kg) of an inhibitor of apoptosis proteins molecule. Methodology & results: Affinity extraction (AE) utilizing immobilized target protein BIR2/BIR3 was used to selectively capture the inhibitor of apoptosis proteins molecule from dog plasma and enable removal of background matrix components. Pretreatment of plasma samples using protein precipitation was found to provide an additional sensitivity gain. A LLOQ of 7.8 pM was achieved by combining protein precipitation with AE. The method was used to support an ultralow dose dog toxicity study.
Conclusion:
AE-LC-MS/MS, utilizing target protein, is a highly sensitive methodology for small molecule quantification with potential for broader applicability.
