Title : N-terminal sequence extension in the glycosylated forms of human
pancreatic stone protein
Abstract :
- The 5-oxoproline N-terminal chain is O-glycosylated on the 5th amino acid residue
- The pancreatic stone protein isolated from human calculi ( PSP ) derives from the immunoreactive protein forms detected in human pancreatic juice ( PSP S2-5) through the tryptic cleavage of the Arg-11-Ile-12 bond
- Among the eleven amino acids of the PSP S2-5 N-terminal extension Z-E-A-Q-T-E-L-P-Q-A-R, the first residue is an oxoproline and the fifth, a threonine , bears the single carbohydrate chain of the protein molecules
- Variations in the glycan chain composition account for the differences in the Mr of PSP S2-5
- The PSP S2-5 forms are very soluble in aqueous solutions between the pH values 5.0-9.0, whereas the proteolysated form is scarcely soluble