Most bacteria use an enzyme belonging to the phospholipase D family as cardiolipin synthase. In contrast, eukaryotes and most actinobacteria use a cardiolipin synthase of the CDP-alcohol phosphatidyltransferase family.This entry represents cardiolipin (CL) synthases that belong to the phospholipase D family. They catalyse the reversible phosphatidyl group transfer from one phosphatidylglycerol molecule to another to form cardiolipin (diphosphatidylglycerol) and glycerol. Bacillus subtilis has three genes (clsA, ywjE and ywiE) for CL synthase; the main role in CL synthesis being played by clsA.