Title :
A new trisaccharide sugar chain linked to a
serine residue in the first
EGF-like
domain of clotting
factors VII and IX and
protein Z . Recently, we determined the complete amino acid
sequence of bovine
factor VII (Takeya, H. et al. (1988) J. Biol
Abstract :
- Chem
- 263, 14868-14877)
- In the course of the studies, we found an unknown serine derivative at position 52 in the first epidermal growth factor-like domain of factor VII
- A pentapeptide isolated from the S-aminoethylated factor VII contained Ser-52 , which could not be identified with a gas-phase sequencer
- The same results were also obtained for a pentapeptide containing Ser-53 of factor IX and protein Z . Component sugar analysis revealed that the peptide contained 1 mol of glucose and 2 mol of xylose.
- This sugar component was also confirmed by high-resolution fast atom bombardment mass spectrometric analysis of the pentapeptide
- The trisaccharide was released from the peptides by means of beta-elimination reaction and its reducing end was identified as pyridylamino-glucose.
- These results indicate the existence of a (Xyl2)Glc-Ser structure Ser structure in factors VII , IX and protein Z . Similar results were obtained for human factors VII , IX and protein Z
- This is the first report of a (Xyl2)-Glc-Ser structure Ser structure in glycoproteins to our knowledge
- The presence of the unique trisaccharide structure in factors VII , IX and protein Z leads us to anticipate its biological role in the tissue factor pathway