Anticoagulant and calcium-binding properties of high molecular weight derivatives of human fibrinogen (plasmin fragments Y).
The present study was undertaken as a step to delineate further the localization of the calcium-binding sites in fibrinogen and to assess the anticlotting properties of fibrinogen degradation products. To this purpose, fragments Y were prepared by plasmin digestion of human fibrinogen in the presence of added Ca2+, and purified. We found that, on a molar basis, fragments Y exhibit twice as much anticlotting activity as fragments X. They possess two calcium-binding sites with Kd = 1.9 . 10(-5) M. Their predominant amino-terminal amino acids are alanine and tyrosine. It is known that one binding site in fragment Y is related to its D moiety. We conclude that the other calcium-binding site may be located in the central domain of the molecule.
D001665:Binding Sites; D001777:Blood Coagulation; D002118:Calcium / Q000378:metabolism*; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011485:Protein Binding
D005338:Fibrin Fibrinogen Degradation Products; C036129:fibrinogen fragment Y; D005340:Fibrinogen; D005341:Fibrinolysin; D002118:Calcium