Western blot comparison of recombinant PA
from the PA/Factor Xa mutant (lanes 1–4) and the commercial PA
(lanes 5–7) product at quantities varying from 1 to 5 μg of the purified rPA
Factor Xa and the LIST PA
. Purified 83 kDa PA/Factor Xa was treated for 30 min at 37°C with bovine plasma Factor Xa resulting in PA20 and PA63 kDa fragments. LF was added and allowed to oligomerize with the PA63 at room temperature for 15 minutes. The mixture was applied to Superose 6 size exclusion column (Amersham-Pharmacia) in PBS and resulted in 3 peaks. The rPA20 was further purified by Immuno-affinity.