Phospholipase A2 releases fatty acids from the second carbon group of glycerol. Perhaps the best known members are secreted snake venoms, but also found in secreted pancreatic and membrane-associated forms. Structure is all-alpha, with two core disulfide-linked helices and a calcium-binding loop. This alignment represents the major family of PLA2s. A second minor family, defined by the honeybee venom PLA2 Structure 1POC and related sequences from Gila monsters (Heloderma), is not recognized. This minor family conserves the core helix pair but is substantially different elsewhere. The PROSITE pattern PA2_HIS, specific to the first core helix, recognizes both families.