Prepilin peptidase is an enzyme found in Type IV filament systems responsible for the maturation of the pilin. This enzyme catalyses the following chemical reactionTypically cleaves a -Gly-Phe- bond to release an N-terminal, basic peptide of 5-8 residues from type IV prepilin, and then N-methylates the new N-terminal amino group, the methyl donor being S-adenosyl-L-methionine.