InterPro domain: IPR033154

The existence of intramembrane, aspartic endopeptidase activity in plants has been confirmed from experimentation of AtSSP (MEROPS identifier A22.A15), a signal peptide peptidase (SPP) homologue from Arabidopsis thaliana (a product of the At2g03120 gene). AtSPP has been shown to digest the myc-prolactin-PP-flag peptide, a substrate of human signal peptide peptidase, an activity that can be inhibited by (Z-LL)2-ketone, a specific SPP inhibitor [ 1 ].

1. Experimental detection of proteolytic activity in a signal peptide peptidase of Arabidopsis thaliana. BMC Biochem. 14, 16