Exam 2 Metabolism

ApoB-100-

VLDL lipoprotein (liver) liver made fat

ApoB-48-

Chylomicrons (small intestine) dietary fat

LPL-

Lipoprotein Lipase

At what point does exocytosis occur in a hepatocyte during VLDL synthesis?

When vesicle is released

LPL is made by?

mRNA messaging to nucleus

LPL monomer is built?

One protein at a time

Dimerization of LPL monomer-

Activates LPL and it is secreted to the interstitial space

How much NADH/NADPH is used to make cholesterol?

12

How much ATP is used to make cholesterol?

18

How much Acetyl-CoA is used to make cholesterol?

18

What is an IDL?

Remanent particle of VLDL after it loses some triglycerides

What receptor inhibits VLDL Resynthesis?

PCSK9

What are the 2 primary bile acids that are produced in the liver?

Choly CoA and Chenodeoxycholyl-CoA

How is cholesterol permanently removed from the body?

By feces

How is cholesterol recycled in the body?

Enterohepatic circulation

Where are bile acids reabsorbed in the small intestine?

Illeum

Reverse Cholesterol Transport does what?

Collects cholesterol from the tissues and returns it to the liver

What does HDL do?

Reverse Cholesterol Transport

Apoprotein A-I does what?

activates LCAT and removes cholesterol from tissues

ABCA1 does what?

Transfers phospholipids and cholesterol to ApoA-I

What is Pre-β HDL?

HDL particle with ApoA-I, phospholipids, and cholesterol esters

What shape is Pre-Beta HDL?

Donut shaped

What is HDL-3?

A HDL particle with more phospholipid and cholesterol esters than Pre-Beta HDL

What is ABCG1?

A transporter that loads more free cholesterol in HDL particles

What esterifies cholesterol in HDL particles?

LCAT

Why is LCAT important and where does it sit?

It allows HDL to be more dense and sits on the surface of HDL

What is CEPT?

Protein that swaps cholesterol esters from HDL for TAGS from ApoB lipoproteins

What is SR-B1?

Receptor in liver cells that collects HDL

What is HTGL?

Enzyme that removes TAGS from HDL in liver

After TAGS are removed from HDL what particle remains?

HDL3

LDL uptake occurs via?

Endocytosis

VLDL Synthesis occurs with what kind of TAGs?

Endogenous

What endogenous particles does the liver synthesize to create VLDL?

TAGS, Chylomicrons, and phospholipids

What do hepatocytes form with VLDL before exocytosis?

A vesicle

What transporter brings FFA into tissues?

CD36

The body uses essential fatty acids to elongate them where do transformations begin?

The omega end

What does Elongase do?

Add 2 carbons to a fatty acid

Desaturase does what?

Adds double bonds to fatty acid

What are the essential fatty acids that the body produces?

20:4n-6, 20:5n-3, 22:6n-3

Why does the body produce ketones?

To supply a substitute for glucose

What is the first step of ketone synthesis?

2 Acetyl-CoA fuse

What does 2 Acetyl-CoA form during ketone synthesis?

acetoacetyl-CoA

What is the first ketone formed in ketone synthesis?

Acetoacetate

What enzyme forms the second ketone in ketone synthesis?

3-hydroxybutyrate dehydrogenase

What is the energy exchange with 3-hydroxybutyrate dehydrogenase?

NADH → NAD⁺

What does 3-hydroxybutyrate dehydrogenase produce from Acetoacetate?

3-hydroxybutyrate

What enzyme in ketone synthesis is bidirectional?

3-hydroxybutyrate dehydrogenase

Ketone body breakdown occurs from what ketone?

Acetoacetate

What is CoA pulled from to make acetoacetyl-CoA in ketone breakdown?

Succinyl-CoA

Ketone breakdown splits acetoacetyl-CoA into what?

2 Acetyl-CoA

Beta Oxidation with Odd Chain fatty acids proceeds

Normally until the odd numbers methyl end

What is the 3 carbon omega end used for odd chain fatty acid beta oxidation?

Propionyl CoA

What enzyme is used to convert Propionyl CoA for TCA?

Propionyl-CoA carboxylase

What is the energy use for Propionyl-CoA Carboxylase?

1 ATP

What substrate does Propionyl-CoA Carboxylase produce?

Succinyl-CoA

Net production for odd chain fatty acid TCA?

1 NADH + 1 FADH2

Beta Oxidation is what?

A way to shorten LCFA's for energy production

What protein releases LCFA in the cytoplasm to be activated?

FABP

What enzyme binds to the LCFA for activation after FABP?

Acyl-CoA synthetase

What does Acyl-CoA synthetase do to LCFA?

Adds CoA and ATP to activate it

What is the LCFA called once activated?

Fatty acyl-CoA

What must be used to bring Fatty Acyl-CoA into the mitochondria?

Carnitine Shuttle

What is CPTI?

Transporter that swaps acyl with carnatine

What is CACT?

Transporter that moves LCFA-carnitine into IMM after CPTI

CPTII is what?

Transporter that swaps carnitine for acyl, making Fatty acyl-CoA

After the Carnitine Shuttle Beta Oxidation begins again with what enzyme?

Acyl-CoA dehydrogenase to produce a double bond

What is the energy exchange for Acyl-CoA dehydrogenase?

FAD to FADH2

What enzyme interacts after a double bond is formed?

3-L-Hydroxyacyl-CoA dehydrogenase

What is the energy exchange with 3-L-Hydroxyacyl-CoA dehydrogenase?

NAD+ to NADH+H

What occurs with 3-L-Hydroxyacyl-CoA dehydrogenase?

2 hydrogens are pulled from the beta carbon

How many rounds of beta oxidation occur?

until the entire LCFA is broken down

Energy production of 1 round of beta oxidation?

2 Acyl-Coa, 1 FADH2, 1 NADH

What are the energy productions from TCA?

1 ATP, 1 FADH2, 3 NADH

MTTP is what?

Transporter that moves TAG into lipoproteins

Efflux protein from HDL particles?

ABCG1

ApoA proteins are specific to what?

HDL

Palmitic Acid?

16:0

Oxidative ATP production of Palmitic Acid?

123 ATP

SLP ATP production of Palmitic Acid?

8 ATP

Total ATP production of Palmitic Acid?

131 ATP

Steric Acid?

18:0

Oxidative ATP production of Steric Acid?

139 ATP

SLP ATP production of Steric Acid?

9 ATP

Total ATP production of Steric Acid?

148 ATP

How many rounds of Beta Oxidation for Steric Acid?

8

How many rounds of Beta Oxidation for Palmitic Acid?

7

How do you calculate ATP production from TCA for fatty acids?

NADH times 3, everything else times 1

What are the important phospholipids?

Phosphatidylcholine and phosphatidylserine

3-hydroxybuturate converted to Acetoacetate energy change?

1 NADH

Acetoacetate TCA yields?

6 NADH, 2 ATP, 2 FADH2

ATP production from Acetoacetate TCA?

20 ATP

ATP production from 3-Hydroxybutyrate TCA?

22.5 ATP

ATP from 1 NADH?

2.5 ATP

ATP from 1 FADH2?

1.5 ATP

What are the 2 essential FA?

Linoleic and Alpha Linolenic

Alpha Linolenic?

18:3n-3

Linoleic Acid?

18:2n-6

20:4n-6?

AA

20:5n-3?

EPA

22:6n-3?

DHA