Selection of Glycans
Chemical analysis of the different glycans attached to the PHF tau and AD phosphorylated tau protein obtained from AD brain was carried out by Sato and coworkers and found that the glycans were rich in High mannose-type sugar chains and truncated N-glycans were also found in both tau in addition to a small amount of sialylated bi- and triantennary sugar chains. Proposed structures and their percent molar ratios of N-glycans obtained from AD P-tau and PHF-tau were reported by sato and coworkers [68]. For the purpose of the study, we have selected the glycan which is present in both PHF tau and AD P-tau, and at the highest proportion. The structure of the glycan is given in supporting information (Figure S7 ).