Abstract
Biotin labeling in combination with mass spectrometry has been widely applied in large-scale biological studies, such as determination of protein partners, protein subcellular localization, and protein post-translational modifications. Previous studies have shown that immunoaffinity enrichment is a better method than streptavidin/avidin purification for site-specific studies of biotinylated molecules. In this study, we made a crucial improvement to the elution phase of the immunoaffinity enrichment step for biotinylated peptides, which involves the addition of a highly organic solvent, and developed a monoclonal anti-biotin antibody that improved the identification number for biotinylated peptides. We then demonstrated its application in the characterization of protein interaction sites for the β2 adrenergic receptor (β2AR) by proximity labeling in living cells. Our research provides an improved and reproducible immunoaffinity enrichment method for site-specific biotin-related research.