Lipid degradation

[DDSelin2mori]

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I’m confused in this subject. According to Kaplan lipids hydrolyzed to fatty acids and glycerol(where does this happen? In peroxisome?) then fatty acids activated (where?) and transfer to mitochondria matrix where beta oxidation pathway occurs and they are converted to acetyl CoA. I’m confused about the place of each step. Wiki says that peroxisome is the place for beta oxidation also I have in my notes that fatty acid degradation occurs in the outer mitochondria membrane. Can any body help me in this subject?
thanks

 

[mddang]

Beta oxidation of lipids occurs in the peroxisomes and in the mitochondria.

 

[joh020340]

B-oxidation mainly occurs in the mito matrix

 

[bigstix808]

According to Kaplan lipids hydrolyzed to fatty acids and glycerol - where does this happen?

lipids are taken from either adipocytes (white adipose tissue) or the diet. The breakdown of the lipids into its constituents (FA's and glycerol) is CAMP mediated (not sure if you need that or not) and takes place in the cytosol. But note that just about all tissue cell types can store fatty acids (not lipids).

In peroxisome?

in an animal cell, once the lipid has been broken down into its constituents (FA's and glycerol), the FA's are then mobilzed to the cell's peroxisomes and mitochondria to undergo B-oxidation. In plant and yeast cells, the peroxisomes are responsible for B-oxidation, not the mitochondria.

then fatty acids activated (where?)

in the cytosol of adipose tissue mainly. they are "activated" as soon as they are removed from the glycerol which adds a CoA group on the end of the FA making it a fatty acyl-CoA.

and transfer to mitochondria matrix where beta oxidation pathway occurs and they are converted to acetyl CoA.

Each turn of the B-oxidation cycle results in having the original FA (fatty acyl-CoA) shortened by 2 carbons, as those 2 carbons are now part of an acetyl-CoA molecule (which will prob then go enter the TCA😎)

clear as mud right!?!? 🙂

 

[DDSelin2mori]

lipids are taken from either adipocytes (white adipose tissue) or the diet. The breakdown of the lipids into its constituents (FA's and glycerol) is CAMP mediated (not sure if you need that or not) and takes place in the cytosol. But note that just about all tissue cell types can store fatty acids (not lipids).


in an animal cell, once the lipid has been broken down into its constituents (FA's and glycerol), the FA's are then mobilzed to the cell's peroxisomes and mitochondria to undergo B-oxidation. In plant and yeast cells, the peroxisomes are responsible for B-oxidation, not the mitochondria.


in the cytosol of adipose tissue mainly. they are "activated" as soon as they are removed from the glycerol which adds a CoA group on the end of the FA making it a fatty acyl-CoA.


Each turn of the B-oxidation cycle results in having the original FA (fatty acyl-CoA) shortened by 2 carbons, as those 2 carbons are now part of an acetyl-CoA molecule (which will prob then go enter the TCA😎)

clear as mud right!?!? 🙂

Wow, really helpful. thanks