Open AccessGlycosaminoglycan Chain of Dentin Sialoprotein Proteoglycan
Author(s) -
Qinglin Zhu,
Ying Sun,
Monica Prasad,
X. Wang,
Albert K. Yamoah,
Yunguo Li,
Jian Q. Feng,
Chunlin Qin
Publication year - 2010
Publication title -
journal of dental research
Language(s) - English
Resource type - Journals
eISSN - 1544-0591
pISSN - 0022-0345
DOI - 10.1177/0022034510366902
Subject(s) - proteoglycan , glycosaminoglycan , bone sialoprotein , chemistry , dentin , dentistry , biochemistry , medicine , extracellular matrix , alkaline phosphatase , enzyme , osteocalcin
Dentin sialophosphoprotein (DSPP) is processed into dentin sialoprotein (DSP) and dentin phosphoprotein. A molecular variant of rat DSP, referred to as "HMW-DSP", has been speculated to be a proteoglycan form of DSP. To determine if HMW-DSP is the proteoglycan form of DSP and to identify the glycosaminoglycan side-chain attachment site(s), we further characterized HMW-DSP. Chondroitinase ABC treatment reduced the migration rate for portions of rat HMW-DSP to the level of DSP. Disaccharide analysis showed that rat HMW-DSP contains glycosaminoglycan chains made of chondroitin-4-sulfate and has an average of 31-32 disaccharides/mol. These observations confirmed that HMW-DSP is the proteoglycan form of DSP (renamed "DSP-PG"). Edman degradation and mass spectrometric analyses of tryptic peptides from rat DSP-PG, along with substitution analyses of candidate Ser residues in mouse DSPP, confirmed that 2 glycosaminoglycan chains are attached to Ser(241) and Ser(253) in the rat, or Ser(242) and Ser(254) in the mouse DSPP sequence.