Fig. 1.

Strategy for BAR labeling of LP. (A) Formalin-fixed floating human brain sections were probed with the anti-PSER129 antibody EP1536Y. (B) Using a biotinylated secondary antibody and ABC, horseradish peroxidase (HRP) was concentrated at the EP1536Y antigenic site. Biotin moieties were deposited near the antibody complex via peroxidase catalyzed oxidation of biotinyl tyramine. (C) Once LP was labeled with biotin, formalin cross-links were reversed in the presence of excess Tris and heat. (D) Liberated biotin-labeled LP-associated proteins could then be purified with streptavidin magnetic beads (E) and digested with trypsin for analysis via liquid chromatography–mass spectrometry (LC/MS).