Truncated A1AT is efficiently secreted to the intercellular fluid. A, Coomassie Brilliant Blue staining of proteins isolated from the IF of leaves infiltrated with StrepA1AT (lane 1), StrepA1AT coinfiltrated with mammalian genes necessary for protein trisialylation (StrepA1ATTriSia; lane 2), and Agrobacteria spp. carrying an empty plasmid (lane 3). A strong band corresponding to truncated A1AT is visible at the position slightly larger than 40 kD. Bands smaller than 40 kD are associated with Agrobacteria spp. infection. B, Coomassie Brilliant Blue staining of A1AT purified from TSP. Lanes 1 and 2 show purified StrepA1AT and StrepA1ATTriSia, respectively. Protein sizes are indicated in kilodaltons.