Figure1: Surfactant composition.
Pulmonary surfactant consists of phospholipids (~90%) with phosphatidylcholine (PC) and phosphatidylglycerol (PG) and phosphatidylinositol (PI) as the major molecular classes in that order. About 10% of pulmonary surfactant is comprised of proteins that are either hydrophobic, (SP-B and SP-C) or hydrophilic and highly oligomeric (SP-A and SP-D) (adapted figure from ref 2).