From Wikipedia,
the free encyclopedia.
Beta oxidation is the
process by which
fats, in the form of Acyl-CoA
molecules, are broken down in the
mitochondria to generate
Acetyl-CoA, the entry molecule for
the
Krebs Cycle.
It occurs in a series of
"cuts". Each time the Acyl-CoA is
cut, two carbons closest to the
end are removed, forming an
Acetyl-CoA molecule. The process
occurs in a specific sequence of
oxidation, hydration, oxidation
and thiolysis. Acyl CoA is first
oxidized to trans-Δ2-Enoyl CoA,
and in the process FAD is
converted to FADH2, to
take up the excess hydrogen. Next,
the trans-Δ3-Enoyl CoA is
converted to L-3-Hydroxyacyl CoA
in a hydration reaction (thus,
water is added). The
L-3-Hydroxyacyl CoA is now
oxidised to 3-Ketoacyl CoA, and
the hydrogens from the water
(added in the hydration) are taken
up by NAD+ being
converted to NADH. Finally, the
3-Ketoacyl CoA is cleaved in a
thiolysis reaction, to form a new
Acyl CoA (two carbons shorter) and
an Acetyl CoA, which can be used
in the Krebs Cycle.
The end products of beta
oxidation for each fat molecule
are one NADH+, one FADH2,
and one Acetyl CoA.
