Phosphatidylglycerol

Phosphatidylglycerol is a glycerophospholipid found in pulmonary surfactant.

The general structure of phosphatidylglycerol consists of a L-glycerol 3-phosphate backbone ester-bonded to either saturated or unsaturated fatty acids on carbons 1 and 2. The head group substituent glycerol is bonded through a phosphomonoester. It is the precursor of surfactant and its presence in the amniotic fluid of the newborn indicates fetal lung maturity.

Approximately 98% of alveolar wall surface area is due to the presence of type I cells, with type II cells producing pulmonary surfactant covering around 2% of the alveolar walls. Once surfactant is secreted by the type II cells, it must be spread over the remaining type I cellular surface area. Phosphatidylglycerol is thought to be important in spreading of surfactant over the Type I cellular surface area. The major surfactant deficiency in premature infants relates to the lack of phosphatidylglycerol, even though it comprises less than 5% of pulmonary surfactant phospholipids.

Biosynthesis

Biosynthesis of Phophatidylglycerol

L-glycerol-3-phosphate is activated by a CTP and pyrophosphate is cleaved off resulting in CDP-diglycerol. Glycerol-3-phosphate is attached to CDP-diglycerol and phosphatidylglycerol phosphate is formed, while CMP is released. The phosphate group is hydrolysed forming phosphatidylglycerol. Two phosphatidylglycerols form cardiolipin, the constituent molecule of the mitochondrial inner membrane.

See also

• glycerol
• cardiolipin

External links

• Phosphatidylglycerols at the U.S. National Library of Medicine Medical Subject Headings (MeSH)