BCHM 316 Chapter Notes - Chapter 14.1*: Mitochondrial Matrix, Thiolase, Coenzyme A
2 May 2018
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Recap of B-oxidation pathway
B-oxidation involves the release of C2 units as acetyl-CoA
- Palmitate (C16): releases 8 C2 units and requires 7 cycles
- Stearate (C18): releases 9 C2 units and
requires 8 cycles
B-oxidation involves oxidation,hydration, oxidation
and cleavage
Oxidation: Fatty acyl coA
Enzyme: acyl-coA dehydrogenase
FAD enters and exists as FADH2 (so a H+ is
being removed from the fatty acyl-CoA)
Hydration: Trans-delta^2-Enoyl-coA
Enzyme: enoyl-coA hydratase
H2O enters; The double bond at carbon 2
gone
Oxidation: 3-L-hydroxyacyl-CoA
Enzyme: 3-L-hydroxyacyl-CoA
dehydrogenase
NAD+ enters and leaves as NADH and H+;
That means two hydrogens left
Cleavage: B-ketoacyl-CoA
Enzyme: B-ketoacyl-CoA thiolase
CoASH enters
Unique features:
- Occurs in mitochondrial matrix
- Involves FAD and NAD as cofactors
- L-intermediate
- Coenzyme A = carrier
- Product = acetyl-CoA ; this is a 2-C product that can be fed into the CAC.
** when acetyl-CoA is cashed into CAC; we have 8 GTP, 24 NADH, and 8
FADH2!
find more resources at oneclass.com
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Peroxisomal B-oxidation
- Occurs in peroxisome (a subcellular organelle)
- Peroxisomal B-oxidation exists to shorten very long chain fatty acids (>22C)
which then B-oxidizes in mitochondria
- Same 4 steps as mitochondria: oxidation, hydration, oxidation cleavage
EXCEPT: FADH2 is recycled by oxidase; H2O2 formed is oxidised by catalase;
therefore, energy is lost
- NADH & Acetyl-CoA is exported from peroxisome to process
find more resources at oneclass.com
find more resources at oneclass.com
