Limited proteolytic digestion of TspDTI. Purified native TspDTI was subjected to proteolytic digestion on immobilized TPCK-trypsin. Lane M, protein marker (GE Healthcare), bands marked: 97 kDa, phosphorylase b; 66 kDa, bovine serum albumin; 45 kDa, ovoalbumin; 31 kDa, carbonic anhydrase; 20.1 kDa, trypsin inhibitor; 14.4 kDa, lysozyme. Lane 1, proteolysis products. All the peptides obtained are marked with horizontal arrows. Of the 5 polypeptides obtained, only peptides 1, 2 and 3 were subjected to N-terminal sequencing.