Evidence for a novel O-linked sialylated trisaccharide on Ser-248 of human plasminogen 2.

Published

Journal Article

Human plasminogen, the inactive precursor of plasmin, exists in two major glycoforms. Plasminogen 1 contains an N-linked oligosaccharide at Asn-289 and an O-linked oligosaccharide at Thr-345. Plasminogen 2 is known to contain only an O-linked oligosaccharide at Thr-345. However, plasminogen 2 displays a further well documented microheterogeneity dependent on the N-acetylneuraminic acid content, which has functional consequences with regard to activation of plasminogen. The proposed structure and number of known oligosaccharide linkages in plasminogen 2 is insufficient to account for this microheterogeneity. In the present study, a combination of trypsin digestion, lectin affinity chromatography, Edman degradation amino acid sequence analysis, carbohydrate composition analysis, and mass spectrometry revealed the existence of a novel site for O-linked glycosylation on plasminogen 2 at Ser-248. Direct evidence for the structure of the carbohydrate was obtained from a combination of lectin affinity chromatography, desialylation experiments, and mass spectrometry analysis. These findings provide a structural basis for some of the observed microheterogeneity, and have implications with regard to the known functional consequences of the extent of sialylation of plasminogen.

Full Text

Duke Authors

Cited Authors

  • Pirie-Shepherd, SR; Stevens, RD; Andon, NL; Enghild, JJ; Pizzo, SV

Published Date

  • March 14, 1997

Published In

Volume / Issue

  • 272 / 11

Start / End Page

  • 7408 - 7411

PubMed ID

  • 9054441

Pubmed Central ID

  • 9054441

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.272.11.7408

Language

  • eng

Conference Location

  • United States