Kinetic and equilibrium metal-ion-binding behaviour reflected in a metal-ion-dependent antigenic determinant in bovine prothrombin. Comparison with bovine prothrombin fragment 1.
Rabbit anti-(bovine prothrombin fragment 1) antibodies were fractionated by using fragment-1 affinity chromatography in the absence of metal ions, and showed an absolute requirement for the presence of metal ions in their interactions with bovine fragment 1 or prothrombin. These antibodies were employed to evaluate both the rate constants for a protein conformation change and the equilibrium metal-ion binding to isolated bovine fragment 1 and intact prothrombin. The close similarity of the rates obtained for the conformation change in fragment 1 and those observed in prothrombin indicated that the same process is involved in both proteins and that the non-fragment-1 region of the prothrombin has essentially no effect on this process in the fragment-1 region. Equilibrium metal-ion-binding studies indicate that the details of the metal-ion-binding process in fragment 1 and prothrombin are essentially the same. We conclude that the metal-ion-binding behaviour of the fragment-1 domain of intact prothrombin is identical with that of isolated fragment 1.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D000939:Epitopes / Q000276:immunology*; D007536:Isomerism; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism*; D011487:Protein Conformation; D011516:Prothrombin / Q000276:immunology / Q000378:metabolism*
D000939:Epitopes; D008345:Manganese; D011516:Prothrombin; D008274:Magnesium; D002118:Calcium