title: Sulfation of a tyrosine residue in the plasmin-binding domain of alpha 2-antiplasmin.
abstract: Sulfation of human alpha 2-antiplasmin, the major plasma inhibitor of fibrinolysis, was examined using both protein isolated from human plasma and protein synthesized and biosynthetically labeled with [35S]sulfate by a human hepatoma-derived cell line. Linkage of sulfate to tyrosine was demonstrated by recovery of labeled tyrosine sulfate after base hydrolysis of sulfate-labeled alpha 2-antiplasmin. Analysis by reverse-phase high performance liquid chromatography of peptides released from alpha 2-antiplasmin by cleavage with trypsin or cyanogen bromide indicated that sulfate is linked to a single segment of the protein. A cyanogen bromide peptide corresponding to the sulfate-labeled peptide was prepared from alpha 2-antiplasmin isolated from human plasma. Consistent with the presence of tyrosine sulfate in this peptide, its chromatographic elution was altered by treatment with acid under conditions which release sulfate from a tyrosine residue. No peptide in the total digest of alpha 2-antiplasmin by cyanogen bromide eluted at the position of the peptide following desulfation, suggesting that all of the protein is in a sulfated form. The sequence of the sulfate-containing cyanogen bromide peptide as determined by sequential Edman degradation, amino acid composition, and fast atom-bombardment-mass spectrometry was: Glu-Glu-Asp-Tyr(SO4)-Pro-Gln-Phe-Gly-Ser-Pro-Lys-COOH. This peptide is a segment of the previously identified plasmin-binding domain of alpha 2-antiplasmin.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D003488:Cyanogen Bromide; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D010446:Peptide Fragments / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism*; D014357:Trypsin; D014443:Tyrosine / Q000378:metabolism*; D000979:alpha-2-Antiplasmin / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D013431:Sulfates; D000979:alpha-2-Antiplasmin; D014443:Tyrosine; D014357:Trypsin; D005341:Fibrinolysin; D003488:Cyanogen Bromide