Hydrolyzes glycerol-phospholipids at the terminal phosphodiesteric bond. Plays an important role in various cellular processes, including phytohormone action, vesicular trafficking, secretion, cytoskeletal arrangement, meiosis, tumor promotion, pathogenesis, membrane deterioration and senescence. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1,2-diacyl-sn-glycero-3-phosphate + choline + H(+) Ca(2+) requirement for activity depends on pH. Active either under acidic conditions with micromolar levels of calcium (PIP2-dependent) or at neutral pH with millimolar levels of calcium (PIP2-independent). C2 domain is a calcium-binding fold, and the binding promotes the protein association with membranes. A lower affinity toward calcium can be anticipated for PLD alpha due to the absence of two potential calcium ligands. The propeptide appears to play a key role in the proper folding and activation of the enzyme. Belongs to the phospholipase D family. C2-PLD subfamily.