A short-chain esterase and phospholipase. a carboxylic ester + H2O = a carboxylate + an alcohol + H(+) a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1,2-diacyl-sn-glycerol + H(+) + phosphocholine Induced by acidic conditions (PubMed:12595455, PubMed:17434691). Induction levels are the same at pH 4.5 and pH 5.0 and decrease as the pH approaches 6.4. No induction is seen at higher pH, nor by oxidative, hypoxic or temperature stress (PubMed:17869077). Induction is maximal after 22 hours exposure to acid. Induction does not depend on sigF, and does not seem to occur in activated murine macrophages (PubMed:12595455). The acid-inducible promoter is found 515 bases upstream of the predicted start site. Three start sites have been proposed for this protein, Met-1, Met-47 and Val-97, this is the longest translation, there is protein sequence (for strain H37Rv) that suggests Met-1 is the correct start. Belongs to the 'GDXG' lipolytic enzyme family. Truncated N-terminus.