Figure 3A.

MS sequencing analyses of the Glu-C products showed that the sequences of the GAG-containing peptides were from the Thr¹⁶² to Arg²⁶⁵ region in the rat DSPP sequence. Vertical bars indicate cleavage sites of Glu-C. The sequences obtained from MS analyses were underlined. Note that the wild-type forms of Glu-C peptides containing Ser²⁴¹ and Ser²⁵³ were not detected, while the wild-type form of Glu-C peptide containing Ser²⁰⁰ was observed with a strong signal in the MS analyses. These observations suggested that Ser²⁴¹ and Ser²⁵³ might be modified, while Ser²⁰⁰ was unlikely to be modified.