| 词条 | Phosphatidylserine | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 释义 |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 590170570 | ImageFile = Phosphatidyl-Serine.png | ImageCaption = Components of phosphatidylserines: Blue, green: variable fatty acid groups Black: glycerol Red: phosphate Purple: serine | IUPACName = | OtherNames = |Section1={{Chembox Identifiers | CASNo_Ref = {{cascite|changed|CAS}} | CASNo = | PubChem = | DrugBank_Ref = {{drugbankcite|changed|drugbank}} | DrugBank = | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 18303 | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = none | MeSHName = |Section2={{Chembox Properties | Appearance = | Density = | MeltingPt = | BoilingPt = |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }}Phosphatidylserine (abbreviated Ptd-L-Ser or PS) is a phospholipid and is a component of the cell membrane. It plays a key role in cell cycle signaling, specifically in relation to apoptosis. It is a key pathway for viruses to enter cells via viral apoptotic mimicry.[1] StructurePhosphatidylserine is a phospholipid (more specifically a glycerophospholipid). It consists of two fatty acids attached in ester linkage to the first and second carbon of glycerol and serine attached through a phosphodiester linkage to the third carbon of the glycerol.[2] Phosphatidylserine coming from plants and phosphatidylserine coming from animals differ in fatty acid composition.[3] Biological functionCell signalingPhosphatidylserine(s) are actively held facing the cytosolic (inner) side of the cell membrane by the enzyme flippase. However, when a cell undergoes apoptosis, phosphatidylserine is no longer restricted to the cytosolic side by flippase. Instead scramblase catalyzes the rapid exchange of phosphatidylserine between the two sides. When the phosphatidylserines flip to the extracellular (outer) surface of the cell, they act as a signal for macrophages to engulf the cells.[4] CoagulationPhosphatidylserine plays a role in blood coagulation (also known as clotting). When circulating platelets encounter the site of an injury, collagen and thrombin -mediated activation causes externalization of phosphatidylserine (PS) from the inner membrane layer, where it serves as a pro-coagulant surface.[5] This surface acts to orient coagulation proteases, specifically tissue factor (TF) and factor VII, facilitating further proteolysis, activation of factor X, and ultimately generating thrombin.[5] In the coagulation disorder Scott syndrome, the mechanism in platelets for transportation of PS from the inner platelet membrane surface to the outer membrane surface is defective.[6] It is characterized as a mild bleeding disorder stemming from the patient's deficiency in thrombin synthesis.[7] BiosynthesisPhosphatidylserine is biosynthesized in bacteria by condensing the amino acid serine with CDP (cytidine diphosphate)-activated phosphatidic acid.[8] In mammals, phosphatidylserine is produced by base-exchange reactions with phosphatidylcholine and phosphatidylethanolamine. Conversely, phosphatidylserine can also give rise to phosphatidylethanolamine and phosphatidylcholine, although in animals the pathway to generate phosphatidylcholine from phosphatidylserine only operates in the liver.[9] Dietary sourcesThe average daily phosphatidylserine (PS) intake from diet in Western countries is estimated to be 130 mg.{{Citation needed|date=October 2016}} PS may be found in meat and fish. Only small amounts of PS can be found in dairy products or in vegetables, with the exception of white beans and soy lecithin. Table 1. PS content in different foods.[10] Soy products are not in this table, because commercial PS is made by enzymatically converting soy phosphatidylcholine (lecithin) to phosphatidylserine, rather than purifying phosphatidylserine from soy.{{cn|date=February 2019}}
SupplementationHealth claimsA panel of the European Food Safety Authority concluded that a cause and effect relationship cannot be established between the consumption of phosphatidylserine and "memory and cognitive functioning in the elderly”, “mental health/cognitive function” and “stress reduction and enhanced memory function”.[3] The reason is that bovine brain cortex- and soy-based phosphatidylserine are different substances and might, therefore, have different biological activities. Therefore, the results of studies using PS coming from different sources cannot be generalized.[3] CognitionIn May, 2003 the Food and Drug Administration gave "qualified health claim" status to phosphatidylserine thus allowing labels to state "consumption of phosphatidylserine may reduce the risk of dementia and cognitive dysfunction in the elderly" along with the disclaimer "very limited and preliminary scientific research suggests that phosphatidylserine may reduce the risk of cognitive dysfunction in the elderly."[11][12] According to the FDA, there is a lack of scientific agreement amongst qualified experts that a relationship exists between phosphatidylserine and cognitive function.[11] More recent reviews have suggested that the relationship may be more robust,[13] though the mechanism remains unclear.[14] Some studies have suggested that whether the phosphatidylserine is plant or animal derived may have significance, with the FDA's statement applying specifically to soy-derived products.[11][15][16][17][18] SafetyTraditionally, PS supplements were derived from bovine cortex (BC-PS). However, due to the risk of potential transfer of infectious diseases such as bovine spongiform encephalopathy (or "mad cow disease"), soy-derived PS supplements have been used as an alternative.[15] Soy-derived PS is designated Generally Recognized As Safe by the FDA.{{Citation needed|date=September 2016}} A 2002 safety report determined supplementation in elder people at a dosage of 200 mg three times daily to be safe.[19] Even so, concerns about the safety of soy products persist, and some manufacturers of PS use sunflower lecithin instead of soy lecithin as a source of raw material for PS production. {{clear}}References1. ^{{cite journal | vauthors = Meertens L, Carnec X, Lecoin MP, Ramdasi R, Guivel-Benhassine F, Lew E, Lemke G, Schwartz O, Amara A | title = The TIM and TAM families of phosphatidylserine receptors mediate dengue virus entry | journal = Cell Host & Microbe | volume = 12 | issue = 4 | pages = 544–57 | date = October 2012 | pmid = 23084921 | pmc = 3572209 | doi = 10.1016/j.chom.2012.08.009 }} 2. ^{{Cite book|title=Lehninger Principles of biochemistry|last=Nelson|first=David|last2=Cox|first2=Michael | name-list-format = vanc |publisher=W.H Freeman and company|year=2008|isbn=9781429208925|edition=5|location=|pages=350 }} 3. ^1 2 {{Cite journal|last=EFSA Panel on Dietetic Products|first=Nutrition and Allergies|date=2010-10-01|title=Scientific Opinion on the substantiation of health claims related to phosphatidyl serine (ID 552, 711, 734, 1632, 1927) pursuant to Article 13(1) of Regulation (EC) No 1924/2006|journal=EFSA Journal|volume=8|issue=10|pages=1749|doi=10.2903/j.efsa.2010.1749|issn=1831-4732}} 4. ^{{cite journal | vauthors = Verhoven B, Schlegel RA, Williamson P | title = Mechanisms of phosphatidylserine exposure, a phagocyte recognition signal, on apoptotic T lymphocytes | journal = The Journal of Experimental Medicine | volume = 182 | issue = 5 | pages = 1597–601 | date = November 1995 | pmid = 7595231 | pmc = 2192221 | doi = 10.1084/jem.182.5.1597 }} 5. ^1 {{cite journal | vauthors = Lentz BR | title = Exposure of platelet membrane phosphatidylserine regulates blood coagulation | journal = Progress in Lipid Research | volume = 42 | issue = 5 | pages = 423–38 | date = September 2003 | pmid = 12814644 | doi = 10.1016/s0163-7827(03)00025-0 }} 6. ^{{cite journal | vauthors = Zwaal RF, Comfurius P, Bevers EM | title = Scott syndrome, a bleeding disorder caused by defective scrambling of membrane phospholipids | journal = Biochimica et Biophysica Acta | volume = 1636 | issue = 2–3 | pages = 119–28 | date = March 2004 | pmid = 15164759 | doi = 10.1016/j.bbalip.2003.07.003 }} 7. ^{{cite journal | vauthors = Weiss HJ | title = Scott syndrome: a disorder of platelet coagulant activity | journal = Seminars in Hematology | volume = 31 | issue = 4 | pages = 312–9 | date = October 1994 | pmid = 7831576 | doi = | url = }} 8. ^{{cite web|last1=Christie|first1=William W. | name-list-format = vanc |title=Phosphatidylserine and Related Lipids: Structure, Occurrence, Biochemistry and Analysis|url=http://aocs.files.cms-plus.com/LipidsLibrary/images/Importedfiles/lipidlibrary/Lipids/ps/file.pdf|website=The American Oil Chemists’ Society Lipid Library|access-date=20 April 2017|date=4 April 2013}} 9. ^{{cite web|last1=Christie|first1=William W.| name-list-format = vanc |title=Phosphatidylcholine and Related Lipids: Structure, Occurrence, Biochemistry and Analysis|url=http://aocs.files.cms-plus.com/LipidsLibrary/images/Importedfiles/lipidlibrary/Lipids/pc/file.pdf|website=The American Oil Chemists’ Society Lipid Library|access-date=20 April 2017|date=12 June 2014}} 10. ^{{cite book |vauthors=Souci SW, Fachmann E, Kraut H | year=2008 | title=Food Composition and Nutrition Tables. Medpharm Scientific Publishers Stuttgart}} 11. ^1 2 {{cite web|url=http://www.fda.gov/food/ingredientspackaginglabeling/labelingnutrition/ucm072999.htm |title=Phosphatidylserine and Cognitive Dysfunction and Dementia (Qualified Health Claim: Final Decision Letter) |last=Taylor |first=Christine L. | name-list-format = vanc |publisher=Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration |date=May 13, 2003 |access-date=23 August 2014}} 12. ^{{Cite web|url=http://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm073992.htm#cognitive|title=Summary of Qualified Health Claims Subject to Enforcement Discretion - Qualified Claims About Cognitive Function|date=|website=|publisher=|access-date=}} 13. ^{{cite journal | vauthors = Glade MJ, Smith K | title = Phosphatidylserine and the human brain | journal = Nutrition | volume = 31 | issue = 6 | pages = 781–6 | date = June 2015 | pmid = 25933483 | doi = 10.1016/j.nut.2014.10.014 }} 14. ^{{cite journal | vauthors = Kim HY, Huang BX, Spector AA | title = Phosphatidylserine in the brain: metabolism and function | journal = Progress in Lipid Research | volume = 56 | pages = 1–18 | date = October 2014 | pmid = 24992464 | pmc = 4258547 | doi = 10.1016/j.plipres.2014.06.002 }} 15. ^1 {{cite web|last1=Smith|first1=Glenn|title=Can phosphatidylserine improve memory and cognitive function in people with Alzheimer's disease?|url=http://www.mayoclinic.org/diseases-conditions/alzheimers-disease/expert-answers/phosphatidylserine/faq-20057764|website=Mayo Clinic|access-date=23 August 2014|date=2 June 2014}} 16. ^{{cite book |title=Treatment of Age-Related Cognitive Decline: Effects of Phosphatidylserine in Anti-Aging Medical Therapeutics | veditors = Crook TH, Klatz RM | volume=2 | publisher = Health Quest Publications | location=Chicago | year=1998 | pages=20–29}} 17. ^{{cite journal | vauthors = Jorissen BL, Brouns F, Van Boxtel MP, Ponds RW, Verhey FR, Jolles J, Riedel WJ | title = The influence of soy-derived phosphatidylserine on cognition in age-associated memory impairment | journal = Nutritional Neuroscience | volume = 4 | issue = 2 | pages = 121–34 | year = 2001 | pmid = 11842880 | url = http://arno.unimaas.nl/show.cgi?fid=4834 | doi = 10.1080/1028415X.2001.11747356 }} 18. ^{{cite journal | vauthors = Kato-Kataoka A, Sakai M, Ebina R, Nonaka C, Asano T, Miyamori T | title = Soybean-derived phosphatidylserine improves memory function of the elderly Japanese subjects with memory complaints | journal = Journal of Clinical Biochemistry and Nutrition | volume = 47 | issue = 3 | pages = 246–55 | date = November 2010 | pmid = 21103034 | pmc = 2966935 | doi = 10.3164/jcbn.10-62 }} 19. ^{{cite journal | vauthors = Jorissen BL, Brouns F, Van Boxtel MP, Riedel WJ | title = Safety of soy-derived phosphatidylserine in elderly people | journal = Nutritional Neuroscience | volume = 5 | issue = 5 | pages = 337–43 | date = October 2002 | pmid = 12385596 | doi = 10.1080/1028415021000033802 }} External links
4 : Phospholipids|Membrane biology|Dietary supplements|Nutrition |
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