title: The human ENO1 gene product (recombinant human alpha-enolase) displays characteristics required for a plasminogen binding protein.
abstract: Plasminogen binds with low affinity in a lysine-dependent manner to many cell types. Previously, a 54 kDa plasminogen receptor found on the surface of U-937 cells was identified as an alpha-enolase-like molecule. The aims of this study were to determine whether recombinant alpha-enolase (r-alpha-enolase), encoded by ENO1, was a plasminogen binding protein and to generate polyclonal antibodies against this antigen. Plasminogen specifically bound r-alpha-enolase with a Kd 1.9 microM and approached saturation at 10 microM. Lysine-dependent plasminogen binding to r-alpha-enolase was demonstrated by a greater than 80% inhibition of binding by the lysine analogues epsilon-amino caproic acid and tranexamic acid, whilst only 14% inhibition occurred with the arginine analogue benzamidine. Removal of the C-terminal lysine residue of r-alpha-enolase with carboxy-peptidase B significantly reduced its plasminogen binding capacity, suggesting that binding required C-terminal lysine residue of r-alpha-enolase. Binding to r-alpha-enolase enhanced the activation rate of plasminogen by urokinase but prevented alpha 2-antiplasmin from binding plasminogen. Taken together, these data suggest that the gene product of human ENO1 encodes an authentic plasminogen binding protein.
authors.affiliation: Department of Biological Sciences, Institute for Molecular Recognition, University of Wollongong, NSW, Australia.
authors.forename: N M
authors.initials: NM
authors.lastname: Andronicos
authors.forename: M
authors.initials: M
authors.lastname: Ranson
authors.forename: J
authors.initials: J
authors.lastname: Bognacki
authors.forename: M S
authors.initials: MS
authors.lastname: Baker
mesh_terms: D001667:Binding, Competitive; D002268:Carboxypeptidases / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D010960:Plasminogen Activators / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000979:alpha-2-Antiplasmin / Q000378:metabolism
chemical_list: C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D000979:alpha-2-Antiplasmin; D010958:Plasminogen; D002268:Carboxypeptidases; D010960:Plasminogen Activators; D010751:Phosphopyruvate Hydratase