Sequential isolation and biochemical analysis of pulmonary surfactant from human lung homogenate.

Pulmonary surfactant was isolated from human lung homogenate after differential and sucrose density gradient centrifugation. Purification of the isolated material was ascertained by electron microscopy and alkaline phosphatase (AKP) specific activity. Elevated levels of phospholipid/protein ration and AKP specific activity were observed in the purified material when monitored at different stages of purification. Biochemical analysis of the isolated material showed that it consisted of 74.08% lipid, 19.06% protein and relatively smaller amounts of nucleic acids, sialic acid and hexoses. Phosphatidyl choline was the predominant phospholipid whereas triglycerides and cholesterol levels were high among neutral lipids. Gas liquid chromatography of the material showed palmitic acid (16:0) as the major saturated fatty acid. These findings indicated that a large scale isolation of surfactant might be possible and utilized for therapeutic treatment of neonatal respiratory distress syndrome.