Western blot analysis of factor XIa activation of plasma factor IX and factor IXR94S using a factor IXa light chain antibody. Factor IXpl (A) or IXR94S (B) (2.7 μmol/L) was activated by factor XIa (18 nmol/L) in TBS containing 10 mmol/L Ca2+ at 37°C. The activation products were sampled at the indicated time intervals, resolved on reducing 12.5% SDS-PAGE, and transferred to PVDF membrane. The membrane was blotted with the JKIX monoclonal antibody, which recognizes the light chain (LC) of factor IXa, and developed using chemiluminescence. The positions of intact factor IX and IXaLC are indicated. The dotted arrow in (B) indicates the usual migration position of the factor IXa light chain. The positions of the molecular weight markers are indicated at left.
