Sequence alignment of human trypsinogen [GenBank: NP_002760] with surface-charged mutant (PRSS1-sc) and guinea pig trypsinogen (Trypsinogen GP, [GenBank: NP_001166359]). Mutated positions of PRSS1 are E31A, E32A, N33H, E79K, R122K, K138L, D153K, Y154N, E157L, and D162N. The catalytic triad of trypsinogen is marked with black boxes. Exchanged amino acids in the mutant are indicated in red boxes. ClustalW [http://embnet.vital-it.ch/software/ClustalW.html] was used for the sequence alignment. Alignment was edited by Bioedit [http://www.mbio.ncsu.edu/bioedit/bioedit.html].