Exact Mass: 808.5734

Exact Mass Matches: 808.5734

Found 500 metabolites which its exact mass value is equals to given mass value 808.5734, within given mass tolerance error 0.05 dalton. Try search metabolite list with more accurate mass tolerance error 0.01 dalton.

PA(20:3(5Z,8Z,11Z)/24:1(15Z))

[(2R)-3-[(5Z,8Z,11Z)-icosa-5,8,11-trienoyloxy]-2-[(15Z)-tetracos-15-enoyloxy]propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(20:3(5Z,8Z,11Z)/24:1(15Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(20:3(5Z,8Z,11Z)/24:1(15Z)), in particular, consists of one chain of mead acid at the C-1 position and one chain of nervonic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(20:4(5Z,8Z,11Z,14Z)/24:0)

[(2R)-3-[(5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoyloxy]-2-(tetracosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(20:4(5Z,8Z,11Z,14Z)/24:0) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(20:4(5Z,8Z,11Z,14Z)/24:0), in particular, consists of one chain of arachidonic acid at the C-1 position and one chain of lignoceric acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(20:4(8Z,11Z,14Z,17Z)/24:0)

[(2R)-3-[(8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoyloxy]-2-(tetracosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(20:4(8Z,11Z,14Z,17Z)/24:0) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(20:4(8Z,11Z,14Z,17Z)/24:0), in particular, consists of one chain of eicosatetraenoic acid at the C-1 position and one chain of lignoceric acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(22:0/22:4(7Z,10Z,13Z,16Z))

[(2R)-2-[(7Z,10Z,13Z,16Z)-docosa-7,10,13,16-tetraenoyloxy]-3-(docosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(22:0/22:4(7Z,10Z,13Z,16Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(22:0/22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of behenic acid at the C-1 position and one chain of adrenic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(22:2(13Z,16Z)/22:2(13Z,16Z))

[(2R)-2,3-bis[(13Z,16Z)-docosa-13,16-dienoyloxy]propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(22:2(13Z,16Z)/22:2(13Z,16Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(22:2(13Z,16Z)/22:2(13Z,16Z)), in particular, consists of one chain of docosadienoic acid at the C-1 position and one chain of docosadienoic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(22:4(7Z,10Z,13Z,16Z)/22:0)

[(2R)-3-[(7Z,10Z,13Z,16Z)-docosa-7,10,13,16-tetraenoyloxy]-2-(docosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(22:4(7Z,10Z,13Z,16Z)/22:0) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(22:4(7Z,10Z,13Z,16Z)/22:0), in particular, consists of one chain of adrenic acid at the C-1 position and one chain of behenic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(24:0/20:4(5Z,8Z,11Z,14Z))

[(2R)-2-[(5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoyloxy]-3-(tetracosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(24:0/20:4(5Z,8Z,11Z,14Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(24:0/20:4(5Z,8Z,11Z,14Z)), in particular, consists of one chain of lignoceric acid at the C-1 position and one chain of arachidonic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(24:0/20:4(8Z,11Z,14Z,17Z))

[(2R)-2-[(8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoyloxy]-3-(tetracosanoyloxy)propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(24:0/20:4(8Z,11Z,14Z,17Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(24:0/20:4(8Z,11Z,14Z,17Z)), in particular, consists of one chain of lignoceric acid at the C-1 position and one chain of eicosatetraenoic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(24:1(15Z)/20:3(5Z,8Z,11Z))

[(2R)-2-[(5Z,8Z,11Z)-icosa-5,8,11-trienoyloxy]-3-[(15Z)-tetracos-15-enoyloxy]propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(24:1(15Z)/20:3(5Z,8Z,11Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(24:1(15Z)/20:3(5Z,8Z,11Z)), in particular, consists of one chain of nervonic acid at the C-1 position and one chain of mead acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(20:3(8Z,11Z,14Z)/24:1(15Z))

[(2R)-3-[(8Z,11Z,14Z)-icosa-8,11,14-trienoyloxy]-2-[(15Z)-tetracos-15-enoyloxy]propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(20:3(8Z,11Z,14Z)/24:1(15Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(20:3(8Z,11Z,14Z)/24:1(15Z)), in particular, consists of one chain of dihomo-gamma-linolenic acid at the C-1 position and one chain of nervonic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PA(24:1(15Z)/20:3(8Z,11Z,14Z))

[(2R)-2-[(8Z,11Z,14Z)-icosa-8,11,14-trienoyloxy]-3-[(15Z)-tetracos-15-enoyloxy]propoxy]phosphonic acid

C47H85O8P (808.5982)

PA(24:1(15Z)/20:3(8Z,11Z,14Z)) is a phosphatidic acid. It is a glycerophospholipid in which a phosphate moiety occupies a glycerol substitution site. As is the case with diacylglycerols, phosphatidic acids can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PA(24:1(15Z)/20:3(8Z,11Z,14Z)), in particular, consists of one chain of nervonic acid at the C-1 position and one chain of dihomo-gamma-linolenic acid at the C-2 position. Phosphatidic acids are quite rare but are extremely important as intermediates in the biosynthesis of triacylglycerols and phospholipids.

PG(18:0/18:1(12Z)-2OH(9,10))

[(2R)-2-{[(9S,10S,12Z)-9,10-dihydroxyoctadec-12-enoyl]oxy}-3-(octadecanoyloxy)propoxy][(2S)-2,3-dihydroxypropoxy]phosphinic acid

C42H81O12P (808.5465)

PG(18:0/18:1(12Z)-2OH(9,10)) is an oxidized phosphatidylglycerol (PG). Oxidized phosphatidylglycerols are glycerophospholipids in which a phosphoglycerol moiety occupies a glycerol substitution site and at least one of the fatty acyl chains has undergone oxidation. As all oxidized lipids, oxidized phosphatidylglycerols belong to a group of biomolecules that have a role as signaling molecules. The biosynthesis of oxidized lipids is mediated by several enzymatic families, including cyclooxygenases (COX), lipoxygenases (LOX) and cytochrome P450s (CYP). Non-enzymatically oxidized lipids are produced by uncontrolled oxidation through free radicals and are considered harmful to human health (PMID: 33329396). As is the case with diacylglycerols, phosphatidylglycerols can have many different combinations of fatty acids of varying lengths, saturation and degrees of oxidation attached at the C-1 and C-2 positions. PG(18:0/18:1(12Z)-2OH(9,10)), in particular, consists of one chain of one octadecanoyl at the C-1 position and one chain of 9,10-hydroxy-octadecenoyl at the C-2 position. Phospholipids are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Similarly to what occurs with phospholipids, the fatty acid distribution at the C-1 and C-2 positions of glycerol within oxidized phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. Oxidized PGs can be synthesized via three different routes. In one route, the oxidized PG is synthetized de novo following the same mechanisms as for PGs but incorporating oxidized acyl chains (PMID: 33329396). An alternative is the transacylation of one of the non-oxidized acyl chains with an oxidized acylCoA (PMID: 33329396). The third pathway results from the oxidation of the acyl chain while still attached to the PG backbone, mainly through the action of LOX (PMID: 33329396).

PG(18:1(12Z)-2OH(9,10)/18:0)

[(2R)-3-{[(9R,10R,12Z)-9,10-dihydroxyoctadec-12-enoyl]oxy}-2-(octadecanoyloxy)propoxy][(2S)-2,3-dihydroxypropoxy]phosphinic acid

C42H81O12P (808.5465)

PG(18:1(12Z)-2OH(9,10)/18:0) is an oxidized phosphatidylglycerol (PG). Oxidized phosphatidylglycerols are glycerophospholipids in which a phosphoglycerol moiety occupies a glycerol substitution site and at least one of the fatty acyl chains has undergone oxidation. As all oxidized lipids, oxidized phosphatidylglycerols belong to a group of biomolecules that have a role as signaling molecules. The biosynthesis of oxidized lipids is mediated by several enzymatic families, including cyclooxygenases (COX), lipoxygenases (LOX) and cytochrome P450s (CYP). Non-enzymatically oxidized lipids are produced by uncontrolled oxidation through free radicals and are considered harmful to human health (PMID: 33329396). As is the case with diacylglycerols, phosphatidylglycerols can have many different combinations of fatty acids of varying lengths, saturation and degrees of oxidation attached at the C-1 and C-2 positions. PG(18:1(12Z)-2OH(9,10)/18:0), in particular, consists of one chain of one 9,10-hydroxy-octadecenoyl at the C-1 position and one chain of octadecanoyl at the C-2 position. Phospholipids are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Similarly to what occurs with phospholipids, the fatty acid distribution at the C-1 and C-2 positions of glycerol within oxidized phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. Oxidized PGs can be synthesized via three different routes. In one route, the oxidized PG is synthetized de novo following the same mechanisms as for PGs but incorporating oxidized acyl chains (PMID: 33329396). An alternative is the transacylation of one of the non-oxidized acyl chains with an oxidized acylCoA (PMID: 33329396). The third pathway results from the oxidation of the acyl chain while still attached to the PG backbone, mainly through the action of LOX (PMID: 33329396).

PG(i-18:0/18:1(12Z)-2OH(9,10))

[(2R)-2-{[(9S,10S,12Z)-9,10-dihydroxyoctadec-12-enoyl]oxy}-3-[(16-methylheptadecanoyl)oxy]propoxy][(2S)-2,3-dihydroxypropoxy]phosphinic acid

C42H81O12P (808.5465)

PG(i-18:0/18:1(12Z)-2OH(9,10)) is an oxidized phosphatidylglycerol (PG). Oxidized phosphatidylglycerols are glycerophospholipids in which a phosphoglycerol moiety occupies a glycerol substitution site and at least one of the fatty acyl chains has undergone oxidation. As all oxidized lipids, oxidized phosphatidylglycerols belong to a group of biomolecules that have a role as signaling molecules. The biosynthesis of oxidized lipids is mediated by several enzymatic families, including cyclooxygenases (COX), lipoxygenases (LOX) and cytochrome P450s (CYP). Non-enzymatically oxidized lipids are produced by uncontrolled oxidation through free radicals and are considered harmful to human health (PMID: 33329396). As is the case with diacylglycerols, phosphatidylglycerols can have many different combinations of fatty acids of varying lengths, saturation and degrees of oxidation attached at the C-1 and C-2 positions. PG(i-18:0/18:1(12Z)-2OH(9,10)), in particular, consists of one chain of one 16-methylheptadecanoyl at the C-1 position and one chain of 9,10-hydroxy-octadecenoyl at the C-2 position. Phospholipids are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Similarly to what occurs with phospholipids, the fatty acid distribution at the C-1 and C-2 positions of glycerol within oxidized phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. Oxidized PGs can be synthesized via three different routes. In one route, the oxidized PG is synthetized de novo following the same mechanisms as for PGs but incorporating oxidized acyl chains (PMID: 33329396). An alternative is the transacylation of one of the non-oxidized acyl chains with an oxidized acylCoA (PMID: 33329396). The third pathway results from the oxidation of the acyl chain while still attached to the PG backbone, mainly through the action of LOX (PMID: 33329396).

PG(18:1(12Z)-2OH(9,10)/i-18:0)

[(2R)-3-{[(9R,10R,12Z)-9,10-dihydroxyoctadec-12-enoyl]oxy}-2-[(16-methylheptadecanoyl)oxy]propoxy][(2S)-2,3-dihydroxypropoxy]phosphinic acid

C42H81O12P (808.5465)

PG(18:1(12Z)-2OH(9,10)/i-18:0) is an oxidized phosphatidylglycerol (PG). Oxidized phosphatidylglycerols are glycerophospholipids in which a phosphoglycerol moiety occupies a glycerol substitution site and at least one of the fatty acyl chains has undergone oxidation. As all oxidized lipids, oxidized phosphatidylglycerols belong to a group of biomolecules that have a role as signaling molecules. The biosynthesis of oxidized lipids is mediated by several enzymatic families, including cyclooxygenases (COX), lipoxygenases (LOX) and cytochrome P450s (CYP). Non-enzymatically oxidized lipids are produced by uncontrolled oxidation through free radicals and are considered harmful to human health (PMID: 33329396). As is the case with diacylglycerols, phosphatidylglycerols can have many different combinations of fatty acids of varying lengths, saturation and degrees of oxidation attached at the C-1 and C-2 positions. PG(18:1(12Z)-2OH(9,10)/i-18:0), in particular, consists of one chain of one 9,10-hydroxy-octadecenoyl at the C-1 position and one chain of 16-methylheptadecanoyl at the C-2 position. Phospholipids are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Similarly to what occurs with phospholipids, the fatty acid distribution at the C-1 and C-2 positions of glycerol within oxidized phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. Oxidized PGs can be synthesized via three different routes. In one route, the oxidized PG is synthetized de novo following the same mechanisms as for PGs but incorporating oxidized acyl chains (PMID: 33329396). An alternative is the transacylation of one of the non-oxidized acyl chains with an oxidized acylCoA (PMID: 33329396). The third pathway results from the oxidation of the acyl chain while still attached to the PG backbone, mainly through the action of LOX (PMID: 33329396).

SM(d18:0/22:6(5Z,8E,10Z,13Z,15E,19Z)-2OH(7S, 17S))

(2-{[(2S,3R)-2-[(5Z,7R,8E,10Z,13Z,15E,17S,19Z)-7,17-dihydroxydocosa-5,8,10,13,15,19-hexaenamido]-3-hydroxyoctadecyl phosphono]oxy}ethyl)trimethylazanium

C45H81N2O8P (808.573)

SM(d18:0/22:6(5Z,8E,10Z,13Z,15E,19Z)-2OH(7S, 17S)) is a type of oxidized sphingolipid found in animal cell membranes. It usually consists of phosphorylcholine and ceramide. SM(d18:0/22:6(5Z,8E,10Z,13Z,15E,19Z)-2OH(7S, 17S)) consists of a sphingosine backbone and a Resolvin D5 chain. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SM has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition, it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2, an enzyme that breaks down sphingomyelin into ceramide, has been found to localize exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme sphingomyelinase, which causes the accumulation of sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.

SM(d18:0/22:6(4Z,7Z,11E,13Z,15E,19Z)-2OH(10S,17))

(2-{[(2S,3R)-2-[(4Z,7Z,10R,11E,13Z,15E,17S,19Z)-10,17-dihydroxydocosa-4,7,11,13,15,19-hexaenamido]-3-hydroxyoctadecyl phosphono]oxy}ethyl)trimethylazanium

C45H81N2O8P (808.573)

SM(d18:0/22:6(4Z,7Z,11E,13Z,15E,19Z)-2OH(10S,17)) is a type of oxidized sphingolipid found in animal cell membranes. It usually consists of phosphorylcholine and ceramide. SM(d18:0/22:6(4Z,7Z,11E,13Z,15E,19Z)-2OH(10S,17)) consists of a sphingosine backbone and a Protectin DX chain. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SM has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition, it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2, an enzyme that breaks down sphingomyelin into ceramide, has been found to localize exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme sphingomyelinase, which causes the accumulation of sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.

SM(d20:1/PGJ2)

(2-{[(2S,3R,4E)-3-hydroxy-2-[(5Z)-7-[(1S,5R)-5-[(1E,3S)-3-hydroxyoct-1-en-1-yl]-4-oxocyclopent-2-en-1-yl]hept-5-enamido]icos-4-en-1-yl phosphono]oxy}ethyl)trimethylazanium

C45H81N2O8P (808.573)

SM(d20:1/PGJ2) is a type of oxidized sphingolipid found in animal cell membranes. It usually consists of phosphorylcholine and ceramide. SM(d20:1/PGJ2) consists of a sphingosine backbone and a Prostaglandin J2 chain. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SM has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition, it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2, an enzyme that breaks down sphingomyelin into ceramide, has been found to localize exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme sphingomyelinase, which causes the accumulation of sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.