Damages membranes of susceptible bacteria (PubMed:17044815). Has antibacterial activity against the Gram-positive bacteria B.megaterium and S.warneri (PubMed:17044815, PubMed:20669184). After a 45-minute treatment with this protein, B.megaterium have no visible pili and are smooth (PubMed:20669184). Has no antibacterial activity against the Gram-positive bacteria B.thuringiensis, S.aureus, S.clavuligerus and B. anthracis, or the Gram-negative bacteria E.coli and A.tumefaciens (PubMed:17044815, PubMed:20669184). Has no hemolytic activity (PubMed:17044815). Does not inhibit the proteinases elastase and cathepsin G (PubMed:17044815). Is not toxic to mice (PubMed:17044815). Expressed by the venom gland. A D-omwaprin has been synthesized to permit cristallization by using a racemic mixture containing equal amounts of L- and D-omwaprin. This D-omwaprin provokes B.megaterium lysis (after 45 minutes of treatment), but fails to inhibit growth of B.anthracis. Belongs to the snake waprin family.