Phosphatidylcholine

1-Oleoyl-2-palmitoyl-phosphatidylcholine

Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues. Dipalmitoylphosphatidylcholine (lecithin) is a major component of the pulmonary surfactant, and is often used in the lecithin–sphingomyelin ratio to calculate fetal lung maturity. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria,[1] including Escherichia coli.[2] Purified phosphatidylcholine is produced commercially.[citation needed]

The name lecithin was derived from Greek λέκιθος, lekithos 'egg yolk' by Theodore Nicolas Gobley, a French chemist and pharmacist of the mid-19th century, who applied it to the egg yolk phosphatidylcholine that he identified in 1847. Gobley eventually completely described his lecithin from chemical structural point of view, in 1874. Phosphatidylcholines are such a major component of lecithin that in some contexts the terms are sometimes used as synonyms. However, lecithin extracts consist of a mixture of phosphatidylcholine and other compounds. It is also used along with sodium taurocholate for simulating fed- and fasted-state biorelevant media in dissolution studies of highly lipophilic drugs.

Phosphatidylcholine is a major constituent of cell membranes and pulmonary surfactant, and is more commonly found in the exoplasmic or outer leaflet of a cell membrane. It is thought to be transported between membranes within the cell by phosphatidylcholine transfer protein (PCTP).[3]

Phosphatidylcholine also plays a role in membrane-mediated cell signaling and PCTP activation of other enzymes.[4]

  1. ^ Jackowski S, Cronan JE, Rock CO (1991). "Chapter 2: Lipid metabolism in procaryotes". In Vance DE, Vance J (eds.). Biochemistry of Lipids, Lipoproteins and Membranes. Elsevier. pp. 80–81. ISBN 978-0-444-89321-5.
  2. ^ Chen F, Zhao Q, Cai X, Lv L, Lin W, Yu X, Li C, Li Y, Xiong M, Wang XG (November 2009). "Phosphatidylcholine in membrane of Escherichia coli changes bacterial antigenicity". Canadian Journal of Microbiology. 55 (11): 1328–34. doi:10.1139/w09-082. PMID 19940943.
  3. ^ Wirtz KW (July 1991). "Phospholipid transfer proteins". Annual Review of Biochemistry. 60 (13): 73–99. doi:10.1146/annurev.bi.60.070191.000445. PMID 1883207.
  4. ^ Kanno K, Wu MK, Agate DS, Fanelli BJ, Wagle N, Scapa EF, Ukomadu C, Cohen DE (October 2007). "Interacting proteins dictate function of the minimal START domain phosphatidylcholine transfer protein/StarD2". The Journal of Biological Chemistry. 282 (42): 30728–36. doi:10.1074/jbc.M703745200. PMID 17704541.