Presentation (4).pdf fatty acid oxidation

Fatty acids oxidation

1. Biochemistry
Eshaeman
Mit-2

2. Fatty acid oxidation and biosynthesis

3. Fatty acid
Define :
fatty acids are organic acids
that consists of a long hydrocarbon
chain attached to a carboxyl group (-
COOH). They are a fundamental
component of lipids , including fats
and oils and play crucial roles in energy
storage and cell structures.

4. Fatty acid oxidation
Fatty acid oxidation, also known as B-oxidation, is the metabolic
process by which the fatty acids are broken down in the
mitochondria ( and peroxisosomesin some cases) to generate
acetyl-CoA, NADH and FADH2 , which are then used to produce
ATP, the energy currency of cell.

5. Overview of fatty acid oxidation ( B-
oxidation)
Where it happens:
• Mitochondria: ( main site)
• Peroxisomes: especially for very long-chain fatty acid .
Steps of B-oxidation.
1.Activation and transport of fatty acids: fatty acids are activated in the
cytoplasm to form fatty acyl-CoA by the enzyme acyl-CoA Synthesis . This
activated fatty acid then needs to be transported into the mitochondria, the site
of B-oxidation. The carnitine shuttle system facilities this transport.

6. 2. Oxidation:
in the first oxidation step , an acyl-CoA dehydrogenase enzyme
removes two hydrogen atoms from the alpha and beta carbons ( C2 and C3) of
the fatty acyl-CoA, cheating a trans double bond between these carbons , this
step generates FADH2 .
3. Hydration:
Enoyl-CoA hydrates adds water across the double bond, forming a
hydroxyl group on the beta carbon ( C3) .

7. 4. Oxidation ( dehydration) :
Another oxidation step, catalyzedby the 3-hydroxyacyl-CoA dehydrogenase,
removes hydrogen atoms from the beta carbon ( C3 ) , oxidising the hydroxyl group to a
ketogoup. This step generates NADH.
5. Thiolysis:
finally, a molecule of CoA cleaves the bond between alpha and beta carbons,
releasing acetyl –CoA then re-enters the beta-oxidation cycle to be further broken down.
6. Repetition:
These four steps are repeated until the entire fatty acid chain is converted to
acetyl-CoA.

9. Clinical relevance:
•Carnitine deficiency:
Impairs transport of fatty acids into mitochondria, hypoketotic
hypoglycaemia.
•MCAD deficiency:
(Medium chain acyl-CoA dehydrogenase) leads to accumulation of
medium-chain fatty acids, lethargy, vomiting and the seizures during fasting.

10. Fatty acid biosynthesis
Biosynthesis is the process by which living organisms produce complex compounds
from simpler one’s, usually using enzymes. It’s essential for growth, repair and
maintaining life.
Key features of biosynthesis
•enzyme-catalysed:
Specific enzymes speed up each step of the process.
•Energy-dependent:
Often require energy input, typically in the form of ATP.

11. •Occurs in cell:
Takes place in organelles like the cytoplasm,
mitochondria and endoplasmic reticulum.
Types of biosynthesis
1. Protein biosynthesis:
Involves: DNA , mRNA ( transcriptions) proteins .
Location: ribosomes in the cytoplasm .
2. Carbohydrates biosynthesis:
Examples: gluconeogensis( formation of glucose from non-
carbohydrates sou

12. 3. Lipid biosynthesis
Includes fatty acid and cholesterol synthesis.
4 . Nucleic acid biosynthesis:
DNA and RNA synthesis from nucleotides.

13. Steps in biosynthesis:
1.Substrate preparation:
simple molecules like amino acids , sugars or nucleotides.
2. Chain initiation :
First enzyme-catalysed reactions.
3 . Chain elongation :
Sequential addition of building blocks.
4. Termination and modification:
Folding , cutting or chemical changes to make the final
product functional.

14. Importance in biology and medicine:
•Critical for cell growth and division.
•Targeted by many antibiotics e.ginhibiting bacterial protein biosynthesis.
•Basis for biotechnology e.ginsulin production via recombinant DNA.

15. Thank you