Lipids 3 Flashcards
Phospholipids
2 FA’s and a Phosphate containing head group on glycerol
Plasmalogens
1 FA, 1 fatty alcohol and polar head group on glycerol–contain fatty alcohol in ETHER linkage–rich in brain, immune system, and heart–deficiency of these been associated w/ downs and alzheimers
Sphingolipids
1 FA, one polar head group on sphingosine (NOT glycerol)–most complex of membrane lipids
What is the composition of the inner and outer leaflet of a lipid bilayer?
Outer leaflet: choline-containing lipids (PC and sphingomyelin)
Inner leaflet: PE and negatively charged lipids (PS)
Synthesis of Phosphatidylcholine
Phosphocholine is activated with CTP; then CDP-choline+diacylglycerol
Synthesis of Phosphatidylethanolamine
similar mechanism to PC (activation by phosphorylation and transferred to CTP
Synthesis of Phosphatidylserine
made from PE exchange of ethanolamine for serine (head group exchange)
Synthesis of Phosphotidylinositol
differs from the other lipids in that the diacylglycerol (NOT the head group) is activated by binding to CTP
What is Cardiolipin?
lipid of inner mito membrance; very important, essential for mito functioning; helps fold electron transport chain protein complexes–degeneration of cardiolipin can be associated w/ alzheimers and parkininsons also normal aging
Phospholipase C
removes phosphate head group from C3 of lipid
Phospholipase A2
It cleaves arachidonic acid from C2 of essential FA linoleic acid (which is a substrate for COX/PGH synthase complex, forming PGH2, a precursor for PGs and TXs)
Prostaglandins–inhibiting of synthesis
involved in inflammatory processes causing vasodilation, stimulate contraction of uterus and can inhibit platelet aggregation–synthesis of prostaglandins can be inhibited by corticosteroids at Phospholipase A2 level and by NSAIDs at COX1/2 and prostalgandin synthase level
Cycloxygenase/PGH Synthase Complex
free arachidonic acid is substrate and is converted to prostoglandin H2–PGH2 is precursor for wide variety of signaling lipid
Which enzyme catalyzes the production of leukotrienes from arachidonic acid?
Lipoxygenase
Critical Step of Plasmalogen Synthesis
Formation of ether linkage–occurs in peroxisomes
What Amino acid is used to build ceramide?
ceramide (lipid component of sphingomyelin) and serine is used to make it
5 classes of Sphingolipids
- Cerebrosides (addition of glucose or galactose)
- sulfatide (sulfate group addition to cerebrosides
- Globosides (2-3 neutral sugars addition)
- Gangliosides (several sugars including NANA)
- Sphingomyelin (addition of phosphatidylcholine)
Ceramide is building block for
ALL glycolipids
