Description

• General description: P5638 is a crude extract of soybean phospholipids. Typical lots of purified soybean phosphatidylcholine have fatty acid contents of approximately 13% C16:0 (palmitic), 4% C18:0 (stearic), 10% C18:1(oleic), 64% C18:2 (linoleic), and 6% 18:3 (linolenic) with other fatty acids being minor contributors. This would calculate to an average molecular weight of approximately 776. Purified phosphatidylcholine is soluble in chloroform and ethanol. Other major phospholipid components include phosphatidylethanolamine and inositol phosphatides. Other phospholipids and neutral lipids such as triglycerides, tocopherols, and sterols may be present. Carbohydrates may also be present.A procedure for determination of the amount of oxidation of egg phosphatidylcholine in a liposome preparation by measurement of the oxidation index has been published.[1] The oxidation index is the ratio of the absorbance at 233 nm to the absorbance at 215 nm. The latter wavelength was chosen since there is little contribution of the fatty acid carbonyl to the absorbance at this wavelength, allowing Beer′s Law to be followed. A method of determining choline content has been published.[2]
• Biochem/physiol Actions: Phosphatidylcholine is the major membrane phospholipid in eukaryotic cells. In addition to being the major structural component of cellular membranes, phosphatidylcholine serves as a reservoir for several lipid messengers. It is the source of the bioactive lipids lysophosphatidylcholine, phosphatidic acid, diacylglycerol, lysophosphatidylcholine, platelet activating factor, and arachidonic acid.[3] Phosphatidylcholine is used for preparation of vesicle suspensions, commonly called liposomes, or as monolayers.[4][5] Monolayers have been formed using a solution of 1% soybean phosphatidylcholine in hexane.[6]Valinomycin-induced changes in membrane potentials of red blood cell and phospholipid (phosphatidylcholine from egg yolk plus cholesterol) vesicle suspensions have been measured using positively-charged, cyanine dyes that fluorimetrically responded to the change in potential.[7]Purified rhodopsin has been incorporated into soybean phosphatidylcholine vesicles.[8]
• Quality: P5638 is a crude soy extract that contains many other lipids.