Fatty acid oxidation

Fatty acid oxidation

Teacher Isaac ​

Fat is one of the most important ways we store energy and the term “burning fat”, actually refers to fatty acid oxidation.

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​a cytosolic enzyme called fatty acyl-CoA synthetase adds a coenzyme A molecule to the end of the fatty acid, turning it into a metabolically active fatty acyl-CoA.

​the fatty acid can’t cross the inner mitochondrial membrane when CoA is attached to it. To get around this problem, we need to free the CoA from the fatty acid.

carnitine palmitoyltransferase 1 and 2 TO THE RESCUE!!!

Multiple Choice

if two people are trapped in the Andes, the person with the less fat content will survive the longest

• TRUE

• FALSE

Fill in the Blanks

Reorder

Reorder the following when fatty acids are ready to enter the target cell

• addition of the CoA to the fatty acid , this requires ATP

• fatty acyl CoA moves to the inner mitochondrial membrane

• replacing CoA for carnitine with the help of CAT

• replacing of carnitine for CoA with the help of CAT2

• regulation of CAT1 with Malonyl-CoA, we don't want to oxidize and break down at the same time

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Reorder

Reorder the following according to the process to start fatty acid oxidation

• blood glucose levels falls

• pancreas secretes glucagon

• increase activity of hormonse sensitive lipase (HSL)

• breaking down of triglycerides

• binding to albumin protein sending it to target cells (i.e liver)

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​an enzyme called acyl-CoA dehydrogenase removes 1 hydrogen from the 2nd carbon, and one hydrogen from the 3rd.

Enzyme provides those hydrogens to FAD --> FADH2

​Conversion of the palmitoyl-CoA to enoyl-CoA in the process.

enoyl-CoA hydratase transfers a hydroxyl group, which is an oxygen linked with a hydrogen, from a water molecule on to the beta carbon of enoyl CoA, making beta-hydroxyacyl-CoA.

​beta-hydroxyacyl-dehydrogenase joins the party!!

new electron carrier involved

here --> NAD+ is reduced into

NADH

this oxidation step occurs at the beta-carbon, fatty acid oxidation is also sometimes called beta-oxidation.

Finally, let's cut those 2 alpha and beta carbons off the fatty acid chain

​a 14-carbon acyl CoA that can enter another cycle of beta-oxidation. So the longer the fatty acid chain, the more cycles, and the more energy we make

Reorder

Reorder the following for the 2nd oxidation step in beta oxidation

• dehydrogenase enzyme removes H atoms from hydroxyacyl-coa

• reduction of NAD+ into NADH

• ketoacyl-coa formation

• β-ketothiolase removes beta and alpha carbons

• 14-carbon fatty acid chain and acetyl-coa is produced

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​THAT IS A LOT OF ENERGY !! TOTALLY WORTH IT RIGHT?

Hotspot

1.- where the first reduction takes place , involves an electron carrier

2.- the name of the product after the removal of the hydrogen atoms

3.- a hydroxyl group is added to produce hydroxyacyl-coa, mark the hydroxyl group

4.- water molecule used to obtain the hydroxyl group

5.- hydratase