Beta oxidation
Fat
• Fat taken up from the blood is either
stored in the intramuscular triglyceride or
used immediately in mitochondria.
• To be able to use fat immediately in the
mitochondria it needs to be broken down
using beta oxidation to get in the TCA
cycle.
Fig 4.1 (p.60)
• The fatty acids must be transported into the mitochondria
for oxidation by using fatty acid transporters, converted
to a fatty acyl CoA.
Acyl CoA synthetase:
Fatty acid + ATP + CoA  Fatty acyl CoA + AMP + PPi
• The transformation of fatty acyl CoA into the
mitochondrial matrix occurs through three different
proteins and the small molecule carnitine.
Fig 6.13 (p.159)
• The beta oxidation begins as soon as the fatty acyl CoA
appears in the matrix, using repeated cycles of four
steps.
• Each cycle is broken down to form a new fatty acyl CoA,
shortened by two carbon atoms, plus an acetyl CoA.
Fig 6.14 (p. 160)
Oxidative Phosporylation
• Oxidative phosphorylation consists of two
pathways: TCA and ETC
• Acetyl CoA is the substrate for the krebs
cycle which can arise form either;
- breakdown of fatty acids using betaoxidation
- Pyruvate (which is produced during
glygolysis in the cytosol).
Fig 4.1 (p.60)