Signal peptidase II (, premurein-leader peptidase, prolipoprotein signal peptidase, leader peptidase II, premurein leader proteinase) is an enzyme.
This enzyme catalyses a chemical reaction. It releases signal peptides from murein prolipoprotein and other bacterial membrane prolipoproteins. It also hydrolyses -Xaa-Yaa-Zaa-(S,diacylglyceryl)Cys-, in which Yaa (Ala or Ser) and Zaa (Gly or Ala) have small neutral sidechains, and Xaa is hydrophobic (preferably Leu).
This enzyme is present in bacterial inner membranes.