Title :
Human serum amyloid P component is an
invariant constituent of amyloid deposits and has a uniquely homogeneous glycostructure
Abstract :
- Human serum amyloid P component ( SAP ) is a normal plasma protein and the precursor of amyloid P component ( AP), a universal constituent of the abnormal tissue deposits in amyloidosis, including Alzheimer disease
- We show here that its single N-linked biantennary oligosaccharide does not display the microheterogeneity usually characteristic of glycoproteins
- The protein and the glycan structures of AP were also invariant , their resistance to degradation suggesting a role in persistence of amyloid deposits
- Asialo- SAP was rapidly cleared from the circulation in mice by a mechanism dependent on terminal galactose residues and was catabolized in hepatocytes
- However blockade of this pathway did not affect the clearance of native SAP
- Rapid hepatic uptake and catabolism of human asialo-SAP in man were also directly demonstrated
- The protein and glycan homogeneity of SAP and the integrity of AP suggest that the complete glycoprotein structure is important for the normal and the pathophysiological functions of this molecule