Title : Further insight into the roles of
the glycans attached to human blood
protein C inhibitor
Abstract :
- Protein C inhibitor ( PCI ) is a 57-kDa glycoprotein that exists in many tissues and secretions in human
- As a member of the serpin superfamily of proteins it displays unusually broad protease specificity
- PCI is implicated in the regulation of a wide range of processes, including blood coagulation, fertilization, prevention of tumors and pathogen defence
- It has been reported that PCI isolated from human blood plasma is highly heterogeneous, and that this heterogeneity is caused by differences in N-glycan structures , N-glycosylation occupancy, and the presence of two forms that differ by the presence or absence of 6 amino acids at the amino-terminus
- In this study we have verified that such heterogeneity exists in PCI purified from single individuals, and that individuals of two different ethnicities possess a similar PCI pattern, verifying that the micro-heterogeneity is conserved among humans
- Furthermore, we have provided experimental evidence that PCI in both individuals is O-glycosylated on Thr20 with a core type 1 O-glycan, which is mostly NeuAcGalGalNAc. Thr20 with a core type 1 O-glycan, which is mostly NeuAcGalGalNAc
- Modeling suggested that the O-glycan attachment site is located in proximity to several ligand-binding sites of the inhibitor