Tag biosynthesis, storage and functions

Department of Biochemistry, Nepalgunj Medical College, Nepal

Saturday, July 2,

2016Rajesh Chaudhary

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Biomedical importance of Acylglycerols

(AG)

The majority of lipids in our body are acylglycerols.

Phospholipids & sphingolipids are major lipid components of cell

membranes.

Some phospholipids have specialized functions.

1. Dipalmitoyl lecithin: major component of lung surfactant, which is

lacking in respiratory distress syndrome of newborn.

2. Inositol phospholipids: … in cell membrane acts as precursor of

hormone second messengers, platelet activating factor.

3. Glycocalyx: … of cell surface are important cell adhesion and cell

recognition factors, acts as receptors for bacterial toxins.

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Either ingested or synthesized, fatty acids have just two

fates:

1. Incorporation into triacylglycerol for storage of

metabolic energy.

2. Incorporation into phospholipid components of

membranes making glycerophospholipids.Saturday, July 2,


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Biosynthesis of triacylglycerols (TAG)

1. Synthesis of glycerol phosphate.

2. Conversion of free fatty acids to its activated

form.

3. Synthesis of molecules of TAG from glycerol

phosphate and fatty acyl CoA.

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1. Synthesis of Glycerol phosphate

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The glucose transporter (GLUT-4) in adipocytes are insulin-dependent. Thus, when

plasma insulin is down, adipocytes have limited capabilities to synthesize glycerol

phosphate and ultimately TAG.

2. Conversion of free fatty acids to its

activated form

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Figure. Assembly and secretion of chylomicrons by intestinal mucosal cells.

3. Synthesis of molecules of TAG from

glycerol phosphate and fatty acyl CoA.

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3. Synthesis of molecules of TAG from

glycerol phosphate and fatty acyl CoA.

Rajesh Chaudhary

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Triacylglycerol synthesis is regulated by

Insulin

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Metabolic changes in T1DM & T2DM

Rajesh Chaudhary

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Metabolic changes in T1DM & T2DM

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Triacylglycerol cycle12

Fates of TAG in the liver and adipose

tissue

In white adipose tissue, TAG is stored in a nearly

anhydrous form as fat droplets in the cytosol of the cells.

Little TAG is stored in liver while most is packaged with

other lipids and Apo proteins to form lipoprotein particles

called VLDL.

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Tag biosynthesis, storage and functions

Science

Transcript of Tag biosynthesis, storage and functions