Fatty Acid Oxidation Flashcards

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1
Q

How are adipocyte TAGs mobilised in metabolic demands?

A

Action of hormone sensitive lipase.

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2
Q

In metabolic demand, what results from the action of hormone sensitive lipase?

A

Forming of free fatty acids, releasing into bloodstream, binding soluble albumin.

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3
Q

Lipases

A

Catalyse hydrolysis of Lipids into constiutent parts.

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4
Q

What happens to the Adipocyte TAG released FFA after release into bloodstream?

A

Undergo catabolism by oxidation that releases free energy.

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5
Q

Beta Oxidation

A

A series of enzyme catalyzed reactions operating in a repetitive fashion, degrading fatty acids by removal of two carbon units.

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6
Q

What must happen to fatty acids before oxidation?

A

FA must be primed for reaction in an ATP-dependent acylation reaction, forming fatty acyl-CoA

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7
Q

Acyl-CoA synthetase

A

Catalyses forming of fatty acyl-coa from fatty acids, before oxidtaion.

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8
Q

Where are Acyl-CoA synthetases found?

A

The ER or OMM.

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9
Q

Carnitine

A

This is used to transport fatty acids across the IMM

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10
Q

Why is caritine required?

A

The long chained Fatty Acyl-CoA resulting from activation cannot freely traverse the INM.

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11
Q

What mediates transfer of acyl groups across the mitochondrial membranes?

A

Carnitine Palmitoyl Transferases 1 and 2 on the internal/external surfaces of the IMM

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12
Q

When the acyl portion of Acyl-CoA transfers to carnitine, how is it then transported into the mitochondria?

A

The carrier protein, carnitine carrier protein transports acyl-carnitine into the mitochondria, transferring free carnitine in the opposite direction.

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13
Q

Pathway of Acyl-CoA transfer into the mitochondria?

A

Acyl groups of cytosolic Acyl-CoA transfer to carnitine, releasing CoA into cytosolic pool, acyl-carnitine transports into MM by carrier protein, where acyl transfer to mitochondrial Acyl, in tandem with carnitine returning to the cytosol.

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14
Q

What are the general steps of beta oxidation?

A

Forming of trans C2-C3 double bond through Acyl-CoA dehydrogenase forming enoyl CoA
Hydration of double bond by enoyl-CoA hydratase forming 3-1, hydroxyacyl-CoA
NAD+ dependent dehydrogenation of 3-1 H-CoA by 3-1 H-CoAD forming beta-ketoacyl-CoA
C2-C3 cleavage catalysed by beta-ketoacyl-CoA thiolase forming acetyl-CoA and a new Acyl-CoA containng two few carbons than original.

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15
Q

How does eta oxidation relate to the ETC?

A

ACDH involves removal of proton at Carbon A and transfer of hydride ion from Carbon B to FAD, forming FADH2, which reoxidises in ETC, supplying it with electrons.

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16
Q

Acyl-CoA structure

A

A skeletal diagram with 6 points, C1 being replaced by a sulfur, with a CoA bound to it, C6 being an R group and C2 having a carbonyl.

17
Q

What is a potential cause of SIDS?

A

Medium chain acyl-CoA dehydrogenase deficiency, as glucose level decrease increases rate of fatty acid oxidation, thus SIDS can be caused by imbalance between glucose and fatty acid oxidation.

18
Q

Function of FA oxidation?

A

Generation of metabolic energy in the form of production of one NADH and one FADH2, with an acetyl CoA each cycle.

19
Q

What happens to beta oxidation derived Acetyl CoA?

A

Via the CAC it generates an additional FADH2 and 3 NADH, each reoxidised through OP to form ATP

20
Q

What is an example of the highly exergonic nature of FA oxidation?

A

Palmitoyl-CoA has C16 fatty acyl group able to go seven cycles of beta oxidation, yielding 7DAH2, 7 NADH and 8 acetyl CoA, where A-CoA yields 24 NADH, 8 GTP and 8 FADH, yielding 77.5 ATP in OP, whilst the 15 FADH2 yields 22.5 ATP.