B-OX/Ketone Bodies/FA synthesis

Acyl-COA dehydrogenase. which step, what does it do, product

1st step of b ox. Use FAD to catalyze the hydride removal and generate a double bond between a and b carbon. Product is trans enoyl-COA.

Enoyl COA hydratase. which step, what does it do, product

Step 2 of b ox. Hydration step, adds water to molecule across double bond to b carbon. Generates hydroxyacylcoa.

Hydroxyacyl-CoA dehydrogenase. which step, what does it do, product

step 3 of b ox. oxidation of alcohol group on b carbon to make ketone on b carbon. produces ketoacyl-coA. use Nad+→ NADH.

Thiolase b ox.what enzyme does it use? which step, what does it do, product

step 4. cleavage between a and b carbon. Use acyl-coa acetyl transferase. generates acyl coa and gernates a new thioester linkage

what is this formula used for:n/2

n/2=# of acetyl-coas made

what is this formula used for:n/2-1

#of FADH2 and NADH made, number of rounds of b ox.

to find total atp, what numbers do you use from TCA cycle?

3 NADH

1FADH

1GTP

Where do you get most of your metabmoic water from?

Oxidation in the TCA cycle. Ox-Phos

enoyl-COA isomerase. when is it used and what does it do?

will move a double bond to 2 & 3. you dont make a new double bond. NO FADH2 made

2,4 dienoyl-COA reductase. when is it used and what does it do?

multiple CIS or conjugated double bonds. You reduce two double bonds and make a new one right in the middle. Uses a NADPH from PPP (NADH equiv.)

delta 3 delta 2 enoyl-COA isomerase. when is it used and what does it do?

used after 2,4 dienoyl coa reductase. moves the double bond formed in the middle to correct position.

After B-ox of odd number fatty acids, what is left?

Propionyl-COA molecule (3C)

Propionyl-COA carboxylase. where is it used, what is it used for? what cofactor does it use. What is its product

Used as 1st step to oxidize propionyl-coa (result from odd number FA). Uses biotin and a ATP. Product is D Methylmalonyl-COA

Methylmalonyl-CoA epimerase. where is it used, what is it used for? what cofactor does it use. What is its product

Second step to oxidze propionyl-COA. no cofactor it moved it around. product is L methylmalonyl coa

Methyl-melonyl-COA mutase. where is it used, what is it used for? what cofactor does it use. What is its product

In third step to oxidze propionyl-COA. coenzyme b12 cofactor. Produces SUCCINYL-COA

How many steps to oxidize propionyl-COA? what are the enzymes and end goal

1. propionyl-COA carboxylase

2. Methylmalonyl-CoA epirimase

3. Methylmalonyl-COA mutase

SUCCINYL-COA

Succinyl-COA has three fates, what are they?

1. generate heme

2. supplement TCA cycle metabolite

3. Generate cytosolic NADPH

Can B ox electrons go into complex II?

No. complex ii is directly connected to TCA reaction

Which FA get oxidized in peroxisomes? whats different in step one compared to mitochondria. does this occur in plants or animals

VLCFA. step 1. acyl coA OXIDASE. fadh2 gets reduced to H2o2 (peroxide). rest of steps are the same. 1.5 less ATP. PLANTS all FA. Animals only VLCFA

what enzyme is present in the peroxisome to process H2o2?

catalase

What happens in the peroxisome when it reaches the end of the thiolase step?

tholase can only recongnize molcules w/ more than 8 carbons. Sends rest of FA to mitochondria for more oxidation (diffuse).

Where does ketone body synthesis occur? what does it start with

Liver. acetyl coa is converted.

What three major areas do ketone bodies get shipped? In what conditions are they shipped

heart, skeletal muscles, brain. They are shipped to be stored for energy. Ketone bodies are the only source of energy when glucose isnt available.

What are the three ketone bodies?

Acetoacetate, acetone, hydroxybutyrate

Thiolase in ketogenisis. What step, what does it do, reactant and product?

step one in ketogenesis. Thiolase catalyzes the reverse reaction and joins 2 acetylCOA together. makes acetoacetyl-COA

HMG-COA synthase. What step, where, what does it do, reactant and product?

2nd step of ketogenesis.takes 3rd acetyl coa, adds it to make HMG COA. acetoacetyl-coa → HMG coa

HMG-COA lyase. What step, where, what does it do, reactant and product?

3rd step of ketogenesis. HMG lyase will cleave off one acetyl coa. HMG COA→ acetoacetate (Ketone body)

Which step of ketogenesis is the commited step?

HMG LYASE. commits HMG to make ketone bodies.

What other mechanisms are Ketone bodies linked to?

Cholesterol synthesis. have similar steps and enzymes.

FATE of acetoacete. What is the reaction if there is a NADH/NAD+ ratio? what enzyme drives reaction?

acetoacetate→ hydroxybutryate. Hydroxybutrate dehydrogenase.

FATE of acetoacete. What is the reaction if there is a NAD+/NADH ratio? what enzyme drives reaction?

hydroxybutryate→ acetoacetate. Hydroxybutrate dehydrognase.

what enzyme is used to make acetoacetate→ acetone?

Acetoacetate decarboxylase. very spontaneous.

Under what hormone conditions does ketone body synthesis occur?

glucagon conditions. Low glucose levels, want to make ketone bodies to supply energy to brain. Liver takes up a lot of the oxaloacetate to do GND under low glucose levels, acetyl coa wont be transported in TCA, causes buildup. Acetyl coa is converted to ketone bodies Liver can make both ketone bodies and glucose.

What happens once acetyle coa is made into ketone bodies? how does ketone bodies get to target areas? what happens once it gets there?

ketone bodies are shipped out of liver into the bloodstream to supplement energy production in brain. ONce its in target cells, it needs to breakdown back into acetyl coa for energy.

What is ketoacidosis?

Long term starvation. Blood ph goes down because ketone bodies are very acididc.

hydroxybutyrate dehydrogenase. What step, where, what does it do, reactant and product?

1st step of ketolysis. hydroxybutryate → acetoacetate. Uses NAD+ . oxidation step.

Ketoacyl-COA transferase. What step, where, what does it do, reactant and product?

2nd step of ketolysis. acetoacetate0> acetoacetyl-coa. USES succinyl-COA and converts to succinate (reverse reaction of TCA). Only present in the target cells and not liver because you dont want to reverse TCA.

Thiolase (ketolysis). What step, what does it do, reactant and product

3rd step in ketolysis. acetoacetyl-coa → 2 acetyl-coa.

Seperate these into where the occur (mitochondria or cytosol): cholesterol, ketone synthesis, b ox, FA synthesis, Fatty acid elongation

mitch:b ox, ketone synthesis, fatty acid elongation

cytosol: fa syn. cholesterol