title: Protective effect of divalent cations in the plasmin degradation of fibrinogen.
abstract: Calcium limits the plasmic proteolysis of fibrinogen fragment D by binding to a specific site on the carboxy-terminal segment of the D gamma chain. Employing sodium dodecyl sulfate-polyacrylamide gel electrophoresis to visualize plasmic fragments, Sr2+, Ba2+, and Mn2+ were found to have an equivalent capacity to limit the degradation of fibrinogen fragment D (Mr 94,000). Mg2+, Fe2+, Co2+, and Zn2+ did not comparably limit the digestion of fragment D. Equilibrium dialysis demonstrated that Ba2+ competitively inhibited Ca2+ binding to fibrinogen, suggesting that the ions occupied the Ca2+ binding site of fibrinogen and thereby limited the plasmic digestion of fragment D. The results suggest that Ca2+, Sr2+, Ba2+, and Mn2+ limit plasmin digestion of fragment D by interacting with a Ca2+ binding site in the D domain of the fibrinogen molecule.
authors.forename: C V
authors.initials: CV
authors.lastname: Dang
authors.forename: W R
authors.initials: WR
authors.lastname: Bell
authors.forename: R F
authors.initials: RF
authors.lastname: Ebert
authors.forename: N F
authors.initials: NF
authors.lastname: Starksen
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008970:Molecular Weight
chemical_list: D002413:Cations, Divalent; D005338:Fibrin Fibrinogen Degradation Products; C015214:fibrinogen D fragment; D005340:Fibrinogen; D005341:Fibrinolysin; D002118:Calcium