University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

230

Pages:

5
Author:

Sheha A.

Oxidation of Fatty Acids The fatty acids in the body are mostly oxidized by β-oxidation. β-oxidation may be defined as oxidation of fatty acids on the β carbon atom resulting in the sequential removal of 2-carbon fragments as acetyl CoA. Activation of Fatty Acids Fatty acids are activated to acyl-CoA by thiokinase or acyl-CoA synthetase and the reaction occurs in 2 steps and requires the ATP, Coenzyme-A, Mg++ Fatty acids then react with ATP to form fatty adenylate which then combines with coenzyme A to produce acyl CoA. In the activation, 2 high energy pyrophosphate are produced since ATP converted to PPi (pyrophosphate) Inorganic pyrophosphatase hydrolyses PPi to phosphate R-CH2-CH2-COO- Fatty acid + ATP Thiokinase PPi Pyrophosphatase R-CH2-CH2-C-AMP Dehydrating agent R-CH=CH-C-AMP Acyl CoA Entry of Fatty acid into mitochondria The inner mitochondrial membrane is impermeable to fatty acids. A specialized carrier system (carnitine shuttle) operates to transport activated fatty acid from cytosol to the mitochondrion. These are 4 steps Acetyl group of acyl CoA is transferred to carnitine catalyzed by carnitine palmitoyl transferase. Entry of Fatty Acids into Mitochondria Acyl-CoA is transported across the membrane to mitochondrial matrix by a specific carrier protein. Carnitine palmitoyl transferase I can convert acyl carnitine to acyl CoA. The carnitine released returns to cytosol for reuse.