Has broad substrate specificity including hydrolysis of phosphatidylcholine with phospholipase A2 (EC 3.1.1.4) and phospholipase A1 (EC 3.1.1.32) activities. Strong expression leads to outer membrane breakdown and cell death; is dormant in normal growing cells. Required for efficient secretion of bacteriocins. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 2-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) Binds 1 Ca(2+) ion per monomer. In the dimeric form the Ca(2+) is bound by different amino acids with binding of each Ca(2+) shared with ligands coming from each monomer (Arg-167 and Ser-172 from 1 monomer, Ser-126 of the other). The Ca(2+) ion may have a role in catalysis. By membrane damage, for example, by phage-induced lysis or temperature shock. The protein is inactive in the monomeric form and active in the dimeric form; calcium is essential for dimer stability. Homodimer; dimerization is reversible, and the dimeric form is the active one. One of the very few enzymes located there. Belongs to the phospholipase A1 family.