Fig. 4.
Amino-terminal sequence analyses of the complex.
Prothrombin (1 μM) was incubated with 750 μg/mL patient IgG in the presence of 5 μM antithrombin III at 37°C for 12 hours. The mixture was applied to immobilized JITAT-17 monoclonal antibody, and the eluate was separated by 10% SDS-PAGE. The gel was electroblotted onto a polyvinylidene difluoride membrane and stained, and appropriate bands were sequenced directly with an ABI Model 476A protein sequencer. The thrombin cleavage site (155R-156S), the factor Xa cleavage sites (271R-272T and320R-321I), and the catalytic triad (363H, 419D, and 525S) of prothrombin are shown. Arrow shows the reactive center of antithrombin III (39 3R-394S).