Fig. 6. Phosphorylation of Thr50 in PHF-Tau from Alzheimer's disease brains. Immunoblots of PHF-Tau with either Phos-Thr50 antibody (1 µg/ml) in the presence of 50 µg/ml of hTau46 (the 412 amino acid form), to further ensure the specificity of the antibody, or anti-Tau serum BR134 (1:1,000). Lanes 1 and 2, PHF-Tau prepared from two Alzheimer's disease brains; lane 3, mixture of recombinant human brain Tau isoforms.