Acting on peptide bonds (peptidases);
Selective hydrolysis of -Xaa-Xaa!Yaa- bonds in which each of the Xaa can be either Arg or Lys and Yaa can be either Ser or Ala
Known from classical flaviviruses (yellow fever, dengue fever). The functional viral peptidase is part of the NS2B protein. Catalytic His, Asp and Ser residues are arranged as in chymotrypsin, but flavivrin is the type example of peptidase family S7.