Category:LBSP


Upper classes: LB LBS


Sphingomyelin

Sphingomyelin (SM) is a ceramide linked with phosphocholine, and is found in nerves of vertebrate, especially myelin sheath. The long-chain base of SM is mostly d18:1 and some d18:0, just like glycosphingolipid. Fatty acid components are length 16-24 and hydroxy fatty acids are not included.[1]

スフィンゴミエリン (SM) はセラミドにホスホコリンが結合した構造で、脊椎動物の神経系、特にミエリン鞘に多くあります。SMの長鎖塩基はスフィンゴ糖脂質と同様に d18:1 が多く、 d18:0 も含まれます。脂肪酸は鎖長 16-24 で構成され、ヒドロキシ酸は通常含まれません。


Biosynthesis

Sphingomyelin synthase is classified into three groups (SMS1, SMS2, SMSr), and two of them synthesize SM at Golgi (SMS1) and plasma membrane (SMS2). In mammals, a protein called CERT transports ceramide from ER to Golgi to synthesize SM. For degradation of SM, many enzymes are known that function in acidic, neutral, or alkaline conditions.[2]

SM合成酵素には3種類あり (SMS1, SMS2, SMSr)、そのうちの2種がゴルジ体 (SMS1) と細胞膜 (SMS2) でSMを合成します。哺乳動物ではSM合成時にセラミドを小胞体からゴルジ体に運ぶタンパク質CERTが知られています。SM分解酵素 (SMase) は種類が多く、酸性、中性、アルカリ性で働く酵素があります。

Mammalian SM synthase family (SMS1 in golgi; SMS2 in plasma membrane)
Phosphatidylcholine + Ceramide → Sphingomyelin + 1,2-Diacylglycerol
SM degradation (Sphingomyelinase) SMase
Sphingomyelin → Ceramide + Phosphocholine

Bioactivity

SM involves in cellular absorption of transferrin, cancer, and arterial sclerosis. Niemann-Pick disease type A / B, an inborn metabolic disease, is caused by accumulation of SM through the shortage of acid sphingomyelinase.

SMはトランスフェリンの細胞内吸収、がん、動脈硬化に関係します。先天性代謝異常症のニーマンピック病A型、B型は酸性SMaseの不足によりSMが蓄積する疾患です。

Ceramide phosphoethanolamine (CPE) and ceramide aminoethylphosphonate (CAEP)

Ceramide phosphoethanolamine (CPE) is formed from a ceramide phosphate linked with ethanolamine. It is often found in insects, trace amount in many animals including bacteria, protozoa, and mammals, and absent in plants or fungi. Ceramide aminoethylphosphonate (CAEP) is similar to CPE but is formed by the C-P bonding. It is found in protozoa, cnidaria, mollusca, and echinodermata.

セラミドホスホエタノールアミン(CPE)はセラミドにリン酸を介してエタノールアミンが結合したものです。昆虫に多く見出されますが、バクテリアから原生生物、哺乳動物まで多くの生物に微量ですが存在します。植物や菌類には見いだされていません。セラミドアミノエチルホスホン酸(CAEP)はCPEと似た構造ですがC-P結合を持ち、原生生物、刺胞動物、軟体動物、棘皮動物などに存在します。

Biosynthesis

There exist three types of sphingomyelin synthase, two of which synthesize CPE. One is SM synthase 2 in cell- and golgi membranes and the other, SM synthase-like protein in the ER lumen (CPE synthase). [3]

スフィンゴミエリン (SM) 合成酵素には3タイプあり、そのうちの2種が CPE を合成します。一つはSM合成酵素SMS2で細胞膜やゴルジ体に存在し、他方は小胞体のスフィンゴミエリン1-関連酵素(SMSr/SAMD8)(CPE synthase)です。

SM synthase 2 family (SMS2)
phosphatidylethanolamine + ceramide → CPE + 1,2-diacylglycerol
CPE synthase (SMS1-related enzyme) SMSr/SAMD8
CDP-ethanolamine + ceramide → CPE + CMP

GIPC

Glycosyl inositol phosphoceramides (GIPCs) were historically referred to as 'phytoglycolipids' (PGLs) for their abundance in plants and fungi.[4][5] Later found in bacteria, protozoa, and other animals (except chordata), PGLs are now called GIPCs. The structure is composed of ceramide with inositol phosphate (inositolphosphoceramide, IPC) and different sugars are attached.

In LipidBank, we classify GIPC into four types:

  1. P2 series: Glucosamine next to inositol (Fungi and Protista) [6]
  2. P3 series: Glucuronic acid next to inositol (Plant)[7]
  3. P4 series: Mannose next to inositol (Fungi)
  4. P5 series: Others
  5. (P1 series is sphingomyelin and ceramide phosphoethanolamine.)

グリコシルイノシトールホスホセラミド (GIPC) は植物に多く含まれるため、歴史的にフィト糖脂質 (phytoglycolipid, PGL) と呼ばれました。その後、菌類や植物だけでなく、バクテリア、原生生物、動物界(脊索動物は除く)での存在がわかり、現在はGIPCと呼ばれます。 構造はセラミドにイノシトールリン酸がついたイノシトールホスホセラミド(IPC)に、様々な糖がついて伸長します。

LipidBankではGIPCを4つに分類しています。

  1. イノシトールの次がグルコサミン (原生動物と菌類)
  2. イノシトールの次がグルクロン酸 (植物)
  3. イノシトールの次がマンノース (菌類)
  4. その他



  1. Merrill, A.H. "Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics" Chem. Rev. 2011, 111, 6387–6422. PMID 21942574
  2. Gault CR, Obeid LM, Hannun YA. "An overview of sphingolipid metabolism: from synthesis to breakdown" Adv Exp Med Biol. 2010;688:1-23. PMID 20919643, Yamaji T, Hanada K. "Sphingolipid metabolism and interorganellar transport: localization of sphingolipid enzymes and lipid transfer proteins" Traffic 2015 16:101-22.PMID 25382749 Zhang Y, Cheng Y, Hansen GH, Niels-Christiansen LL, Koentgen F, Ohlsson L, Nilsson A, Duan RD. "Crucial role of alkaline sphingomyelinase in sphingomyelin digestion: a study on enzymeknockout mice" J Lipid Res. 2011 52:771-81 PMID 21177474
  3. Vacaru AM, Tafesse FG, Ternes P et al. (2009) "Sphingomyelin synthase-related protein SMSr controls ceramide homeostasis in the ER" J Lipid Res 185(6):1013-1027. PMID 19506037
  4. Carter HE, Celmer WD, Galanos DS, Gigg RH, Lands EM, Law JH, Mueller KL, Nakayama T, Tomizawa HH, Weber E. 1958. Biochemistry of the sphingolipides. X. Phytoglycolipide, a complex phytosphingosine-containing lipide from plant seeds. Journal of the American Oil Chemists Society 35: 335–343
  5. Carter HE, Brooks S, Gigg RH, Strobach DR, Suami T. 1964. Biochemistry of the sphingolipids. XVI. Structure of phytoglycolipid. Journal of Biological Chemistry 239: 743–746
  6. Cerbón J, Falcon A, Hernández-Luna (2005) "Inositol phosphoceramide synthase is a regulator of intracellular levels of diacylglycerol and ceramide during the G1 to S transition in Saccharomyces cerevisiae" Biochem J. 2005 388(Pt 1):169-176. PMID 15560753
  7. Buré C, Cacas JL, Mongrand S, Schmitter JM (2014) "Characterization of glycosyl inositol phosphoryl ceramides from plants and fungi by mass spectrometry" Anal Bioanal Chem. 406:995-1010. PMID 23887274

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