Beta oxidation of fatty acids

Step 1(Activation of fatty acid)

A long chain fatty acid is activated in the cytosol by the addition of CoA-SH and by enzyme acyl-CoA synthetase, using ATP. Resulting in acyl-CoA

Step 2

Using enzyme CAT-1, carnitine attaches to the molecule and CoA-SH is kicked off to form acylcarnitine so that it can be transported into the mitochondria.

Step 3

In the mitochondria, CAT-2 enzyme adds CoA-SH to the molecule and carnitine is kicked off to regenerate acyl-CoA for subsequent beta oxidation.

Step 4

The acyl-CoA is oxidized into enoyl-CoA by the enzyme acyl-CoA dehydrogenase, introducing a double bond. NAD+ is reduced to NADH in the process.

Step 5

The enoyl-CoA undergoes hydration by the enzyme enoyl-CoA hydratase, adding a water molecule to form beta hydroxyacyl-CoA.

Step 6

The beta hydroxyacyl-CoA is oxidized to form beta ketoacyl-CoA by the enzyme beta-hydroxyacyl-CoA dehydrogenase, reducing NAD+ to NADH.

Step 7

The beta ketoacyl-CoA undergoes thiolysis, cleaved by the enzyme thiolase and a CoA-SH is added resulting in the formation of a free fatty acyl-CoA and an acetyl-CoA molecule.

difference between short chain fatty acid and long chain fatty acid for beta oxidation

a short chain fatty can enter the mitochondria directly and get activated through the same process of long chain fatty acids get activation in the cytosol