Chondroitin 4-sulfate covalently cross-links the chains of the human blood protein pre-alpha-inhibitor.
The human blood protein pre-alpha-inhibitor is composed of one heavy and one light protein chain. The chains are covalently linked to each other by a structure that has not previously been described, which we designate a protein-glycosaminoglycan-protein (PGP) cross-link. A combination of protein and carbohydrate analytical techniques indicates that the interchain linkage is mediated by a chondroitin 4-sulfate glycosaminoglycan that originates from a typical O-glycosidic link to Ser-10 of the light chain. The heavy chain is esterified, via the alpha-carbon of its C-terminal Asp, to C-6 of an internal N-acetylgalactosamine of the glycosaminoglycan chain. This PGP cross-link may be present in other proteins, but could have been overlooked due to the heterogeneous behavior of proteins containing glycosaminoglycan.
Enghild
J J
JJ
Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710.
Salvesen
G
G
Hefta
S A
SA
Thøgersen
I B
IB
Rutherfurd
S
S
Pizzo
S V
SV
D000596:Amino Acids / Q000737:chemistry; D001798:Blood Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002241:Carbohydrates / Q000737:chemistry; D002809:Chondroitin Sulfates / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry; D011498:Protein Precursors / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000378:metabolism*
D000596:Amino Acids; D001798:Blood Proteins; D002241:Carbohydrates; D003432:Cross-Linking Reagents; D011498:Protein Precursors; D014361:Trypsin Inhibitors; C061151:pre-alpha-trypsin inhibitor; D002809:Chondroitin Sulfates