CM3 subunits of the tetrameric alpha-amylase inhibitors expressed in Butte 86. The N-terminus of a WTAI-CM3 inhibitor determined by Shewry et al.  is denoted by the bracket. Peptides obtained by MS/MS that distinguish individual WTAI-CM3 proteins are enclosed in shaded boxes. Total MS/MS coverages of WTAI-CM3 Bu-1 and WTAI-CM3 Bu-2 in protein spot 264 from Dupont et al.  were 90 and 76%, respectively (Additional file 5).