Identification and characterization of Theba pisana prohormone convertases (PCs). (A) Amino acid alignment between PC1 and PC2 shows strong homology, especially within the catalytic region, shown schematically in (B); shown are signal (pre; yellow), pro domain (blue) and catalytic region (red). (C) T. pisana PCs cluster within the PC1, PC2 and furin-type convertases. Scale bar represents amino acid substitutions. Genbank accession numbers for all PCs are listed in Additional file 4.