LipidMetabolismI

Dr.KevinAhern

Fat and Glycerophospholipid Synthesis

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Phosphatidic Acid

Glycerol-3-P

Fat (Triacylglycerol)

Glycerophospholipids

Fat Breakdown

Signaling

Catalysis

Glycero PhosphoLipid

Glycerophospholipids / Phosphatides

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• Glycerophospholipic Synthesis Involves CDP-Activated Intermediate

• Two General Mechanisms

Phosphatidic Acid + CTP + PPi

CDP-Diacylglycerol

Phosphatidyl Portion of Final Product

Will Split Off as CMP

CDP-Diacylglycerol + Inositol

+

Phosphatidylinositol + CMP

CDP

+ CMP

• Second Mechanism - Activate Add-on Molecule

ATP ATP CTP PPi

Ethanolamine Phosphorylethanolamine CDP-Ethanolamine

Splits OffAdds to Diacylglycerol

CDP-Ethanolamine + CMP + Diacylglycerol Phosphatidylethanolamine

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Sphingolipid Biosynthesis

SphingolipidsBranch Point

Amino Acid

Fatty Acid

Ceramide Synthesis

Sphingolipid Synthesis

MembraneLipidMetabolism• Sphingolipids

PhosphocholineR = OR

PhosphoethanolamineR =

Single SugarR =

Complex SugarR =

Sphingomyelin

Cerebroside

Ganglioside

Sphingolipid Breakdown Diseases

Cholesterol Biosynthesis

Acetyl Group

Cholesterol

Branch Point

Cholesterol Biosynthesis

IPP + DPP

IPP DMAPP

Geranyl-PP

Lanosterol

Acetyl-CoA

Farnesyl-PP

IPP

Squalene2

5 Carbons Each

10 Carbons

15 Carbons

30 Carbons

30 Carbons

Lanosterol Cholesterol

19 Steps

Cholesterol Metabolism

Cholesterol Bile AcidsExcretion

Mineralocorticoids &

Corticosteroids

Cholesterol Metabolism

Lipid Movement From the Diet

Removal of 2 Fatty Acids

Reattachment of 2 Fatty Acids

Inside IntestineOutside Intestine

Apolipoprotein Complexes

Chylomicron

Receptor-mediated Endocytosis

Foam Cell Aggregate

Carotid Artery Plaque