Sphingolipids:
There are two types of sphingolipids: sphingophospholipid (Sphingomyelins) &
Sphingoglycolipids. Both share the presence of sphingosine as their backbone and
one fatty acid; however, they differ in the head group connected to sphingosine
Sphingophospholipid head group: phosphocholine
Sphingoglycolipids head group: Mono or oligosaccharide
Structure of sphingolipids
Notice that C1 is connected to an oxygen and the head group, while C2 is associated
with Nitrogen connected to a fatty acid chain. Moreover, C3 is associated with an
OH group and an unsaturated alkyl group containing a C=C (double bond).
, Ceramides are the basic sphingolipids
and the precursors with H connected
to sphingosine as the head group ( it
will be ionized at physiological pH).
Recall: Phosphatidic acids is the basic
glycerophospholipids.
Glycosphingolipids are further
classifiedinto: Cerebroside ( the
basic type),Globosides
(Lactosylceramides),
Gangliosides, and Sulfatides.
Synthesis of sphingomyelin
Palmitoyl CoA (activated 16-C fatty acid) condenses with
serine ( 3-C unit, the Nitrogen source) forming Sphinganine
(dihydrosphingosine).
CO2 is released (decarboxylation)
CoA is released
NADPH is needed as a source of electrons to
reduce an intermediate product (not
shown) into Sphinganine (Redox reaction)
Could be considered as a transamination as N is
transferred from serine into another molecule.
Accordingly, reaction requires pyridoxal
phosphate
Then another activated fatty acid in the form of Fatty acyl CoA is transferred to
Sphinganine ,specifically to the serine portion. Moreover, FAD is Reduced to
FADH2 to oxidize the Palmitoyl (forming the double bond), and by this Ceramide is
produced.
There are two types of sphingolipids: sphingophospholipid (Sphingomyelins) &
Sphingoglycolipids. Both share the presence of sphingosine as their backbone and
one fatty acid; however, they differ in the head group connected to sphingosine
Sphingophospholipid head group: phosphocholine
Sphingoglycolipids head group: Mono or oligosaccharide
Structure of sphingolipids
Notice that C1 is connected to an oxygen and the head group, while C2 is associated
with Nitrogen connected to a fatty acid chain. Moreover, C3 is associated with an
OH group and an unsaturated alkyl group containing a C=C (double bond).
, Ceramides are the basic sphingolipids
and the precursors with H connected
to sphingosine as the head group ( it
will be ionized at physiological pH).
Recall: Phosphatidic acids is the basic
glycerophospholipids.
Glycosphingolipids are further
classifiedinto: Cerebroside ( the
basic type),Globosides
(Lactosylceramides),
Gangliosides, and Sulfatides.
Synthesis of sphingomyelin
Palmitoyl CoA (activated 16-C fatty acid) condenses with
serine ( 3-C unit, the Nitrogen source) forming Sphinganine
(dihydrosphingosine).
CO2 is released (decarboxylation)
CoA is released
NADPH is needed as a source of electrons to
reduce an intermediate product (not
shown) into Sphinganine (Redox reaction)
Could be considered as a transamination as N is
transferred from serine into another molecule.
Accordingly, reaction requires pyridoxal
phosphate
Then another activated fatty acid in the form of Fatty acyl CoA is transferred to
Sphinganine ,specifically to the serine portion. Moreover, FAD is Reduced to
FADH2 to oxidize the Palmitoyl (forming the double bond), and by this Ceramide is
produced.
