Beta oxidation of fatty acids in brief with the steps and carnitine shuttle.

1. BETA OXIDATION.. By : Shlok Mathur

2. IMPORTANCE OF FATTY ACIDS..
Fatty acids are building blocks of
phospholipids and glycolipids
Many proteins are modified by the
covalent attachment of fatty
acids, which targets them to
membrane location.
They are stored as TAG’s
Fatty acid derivatives serves as
hormones and intracellular
messengers

3. TYPES OF FATTY ACID OXIDATION..
Beta Oxidation : major mechanism, occurs in the mitochondrial
matrix. 2-C units are released as acetyl CoA per cycle.
Alpha Oxidation : predominantly takes place in brain and liver, one
carbon is losr in the form of CO2 per cycle.
Omega Oxidation : minor mechanism, but becomes important in
conditions of impaired beta oxidation.
Peroxisomal Oxidation : mainly for trimming of very long chgain fatty
acids.

4. β-oxidation..
2-carbon atoms are removed in the form of
acetyl-Co-A at the end of each cycle
Fatty acid is subjected to prior activation
before oxidation
Activation of Fatty acid takes place outside
the mitochondria
Fatty acid cannot penetrate through inner
mitochondrial membrane so they are
transported with the help of carnitine
shuttle inside the mitochondria
B-oxidation takes place in all the cells
having mitochondria
Strictly aerobic
Cyclic process, in each cycle 4 steps are
involved
i)Dehydrogenation
ii)Hydration
iii)Dehydrogenation
iv)Thiolytic cleavage

5. ACTIVATION OF
FATTY ACIDS..
Fatty acids must be first
activated so that they participate
in metabolic pathway. The
activation requires energy which
is provided by ATP.

6. TRANSPORT OF FATTY
ACYL COA INTO
MITOCHONDRIA…
The carnitine shuttle system..

7. STEPS OF BETA OXIDATION..
1. Dehydrogenation: Removal of
2 H atoms.
2. Hydration: Addition of one
molecule of H2O.
3. Dehydrogenation: Removal of
2 hydrogen atoms.
4. Thiolytic cleavage.

8. ENERGETICS..
Regulation Of Beta Oxidation..
1. The availability of free fatty acids
(FFA) regulates the net utilization
through beta oxidation.
2. The level of FFA is controlled by
the Glucagon: Insulin ratio.
3. Glucagon increases FFA level and
Insulin has opposite effect.
Palmitic acid, C15H31COOH, on complete
oxidation (β-oxidation) produces 8 acetyl-CoA
(Refer discussion above). Transport of electrons
in respiratory chain from reduced Fp and NAD in
each cycle produces 5 (five) high energy
phosphate bonds.
Hence, 7 cycles (7 × 5) = 35 ~ P
Total 8 molecules of acetyl-CoA, When oxidised
in TCA cycle will produce = 12 × 8 = 96 ~ P
Total high energy phosphate bonds produced =
131 ~ P
Total = 131 ~ P
In initial activation of FA~ P bond utilised = –2 ~ P
Total gain = 129 ~ P

9. FATTY ACID OXIDATION..
Odd Chain..
Oxidation of odd chain fatty
acids is similar to that of even
chain fatty acids.
At the end 3 carbon unit,
propionyl CoA is produced.
Propionyl CoA is converted into
Succinyl CoA.
Succinyl CoA is an intermediate
in TCA cycle.
Propionyl CoA is Gluconeogenic.
Unsaturated...
The oxidation of unsaturated
FA is similar to the saturated
FA except for one difference .
There is less energy
production for double bond
i.e. 2 ATP’S are less produced
because the double bond is
already present . Therefore
the first step of
dehydrogenation is bypass .
At the first step FAD is used
as coenzyme which is
oxidized in the ETC producing
2 ATP’S . When this step is
bypassed no ATP is produced

10. CLINICAL SIGNIFICANCE OF EVEN
CHAIN FATTY ACIDS..
1. Carnitine Deficiency
2. CAT 1/ CAT 2 Deficiency
3. Jamaican Sickness
4. Sudden Infant Death Syndrome
5. Acute Fatty Liver of Pregnancy.

11. CLINICAL SIGNIFICANCE OF OTHER
FATTY ACIDS..
Odd chain Fatty Acids..
Methyl Malonyl Acid Urea
Refsums Disease.
Peroxisomal oxidation..
Zellwenger Syndrome
(cerebro-hepato-renal
Syndrome)

12. THANK YOU.. Doubt..??