LIPID 2 Flashcards
Sphingophospholipids
- Lipids not containing glycerol
- composed of a sphingosine backbone
linked to a fatty acid via an amide bond. - many types differ in their hydrophilic attachments.
Derivatives of ceramide, formed by esterification of a fatty acid with the amino group of sphingosine.
types
Anki
Glycosphingolipids/ Glycolipids
-contain both carbohydrate and lipids components.
* The precursors of both phosphorylated and glycosylated sphingolipids is ceramide.
* Essential components of all membranes in the body,but greatest amounts in nerve tissue.
* Located in the outer leaflet of plasma membrane, thus interact with ECF
* Role: Regulate cellular interactions.
Cerebrosides
The simplest neutral glycosphingolipids.
* Consist of ceramide (sphingosine and FA) and a monosaccharide (Glucose or Galactose)
bound by a β-glycosidic bond to the C1.
* Found predominantly in the brain (white matter) and peripheral nervous tissue, with high concentrations in the myelin sheath.
* Functions : Provide protective coating to each nerve , Act as an insulator and Important in nerve conduction
* Galactocerebroside,common in myelin
Glucocerebroside, is primarily an intermediate in the synthesis and degradation of the more complex glycosphingolipids.
Cerebrosides diseases
-Autosomal recessive disease
Accumulation of glucocerebrosides is Gaucher’s disease-b glucosidase deficiency.
b galactocerebroside accumulation - Krabbe disease.-deficient in b galactosidase.
Large spleen and liver
Affects CNS and muscle tone.
Accumulation of cerebrosides in liver and spleen causes enlargement
Globosides
- Produced by attaching additional monosaccharides to a glucocerebroside.
- E.g: ceramide-glucose-galactose (AKA lactosylceramide). The additional monosaccharides can include substituted sugars such as N- acetylgalactosamine.
Acidic Glycosphingolipids
- negatively charged at physiologic pH.
- negative charge is provided by N-acetylneuraminic acid ([NANA] in gangliosides, OR by sulfate groups in sulfatides.
Gangliosides
- most complex glycosphingolipids
- Found primarily in the ganglion cells of the CNS, nerve endings.
- Derivatives of ceramide oligosaccharides and contain one or
more molecules of NANA. - Notation: G (for ganglioside) plus a subscript M, D, T, or Q to
indicate whether there is one (mono), two (di), three (tri),
or four (quatro) molecules of NANA in the ganglioside.
accumulation of NANA- containing glycosphingolipids in cells.- lipid disorder
- The most important gangliosides present in the brain are GM1, GM2, GD, and GT
- Tay-Sachs disease : GM2 gangliosides breakdown defect.
- GM1, a more complex ganglioside derived from GM3 , is of considerable biologic interest, as it is known to be the receptor in human intestine for cholera toxin (CTX).
Sulfatides
- Sulfated galactocerebrosides that are negatively charged at physiologic pH (due to sulfate group).
- found predominantly in the brain and kidneys.
- degraded in the lysosomes.
excess can lead to pathological conditions. - Metachromatic leukodystrophy, lysosomal storage disorder characterized by the accumulation of lysosomal sulfatides due to a deficiency in lysosomal sulfatase, arylsulfatase A.
gaucher disease symptoms
- progressive neurologic symptoms
-pulmonary involvement
-hepatosplenomegaly
-thrombocytopenia and anemia - skeletal involvement
Krabbe disease symptoms
- feeding difficulties
- unexpected crying
- extreme irratibility
- fever with no clear etiology
- development delays
- muscle spasms
- poor head ctrl
- frequent vomiting
- developmental regression
