Mitochondrion
are self duplicating, semi
autonomous, double membrane bound, cytoplasmic organelles found in all
eukaryotic cells.
Peroxisomes are microbodies or self duplicating;
single membrane bound organelles present in all eukaryotic cells. They
contain oxidative enzymes, such as catalase and urate oxidase, at such high
concentrations.
Mitochondrion vs Peroxisomes
Mitochondrion
|
Peroxisomes
|
Double membrane bound organelle
|
Single membrane bound organelle
|
Semi-autonomous organelle, contains DNA called mt DNA or
mitochondrial genome
|
No DNA
|
New mitochondrion arise by growth and fission
|
New peroxisome also arise by
growth and fission
|
Mitochondrial proteins are coded by both mitochondrial DNA and
Nuclear DNA
|
Peroxisomal proteins are encoded by nuclear DNA
|
Mitochondrial proteins are made on free cytoplasmic ribosomes and ribosomes
inside mitochondrion
|
Peroxisomal proteins are made on free cytoplasmic ribosomes
|
Unfolded Proteins are post‐translationally imported with the help of
proteins complexes called TIM, TOM and OXA complex
|
Folded Proteins are post‐translationally imported with the help of
proteins coded by PEX genes named peroxins
|
Import signal sequence is called "mitochondria-targeting
sequence" (MTS), which is located at the amino termini or N termini of
the preproteins or unfolded protein
|
Import signal is a specific
sequence of three amino acids located at the C terminus of many peroxisomal
proteins
|
Signal sequences at N terminus are removed after import by a protease
called signal peptidase in the mitochondrial matrix.
|
Generally, Signal sequences are not removed after import
|
Function: Oxidative phosphorylation and ATP synthesis which is used
to drive various cellular activities.
Matrix is the site of β
oxidation
|
Functions: Involved many metabolic processes or oxidative reactions,
such as β‐oxidation of very long‐chain fatty acids releasing energy,
and synthesis of plasmalogen,
an important membrane component in brain and heart and bile acids as well as
generation and degradation of hydrogen peroxide during detoxification.
|
TIM: Translocase Inner Membrane; TOM: Translocase Outer
Membrane
Reference:
- Platta, H. W., & Erdmann, R. (2007). The peroxisomal protein import machinery. FEBS letters, 581(15), 2811-2819.
- Rehling, P., Wiedemann, N., Pfanner, N., & Truscott, K. N. (2001). The mitochondrial import machinery for preproteins. Critical reviews in biochemistry and molecular biology, 36(3), 291-336.
- Fujiki, Yukio, Okumoto, Kanji, and Honsho, Masanori(Apr 2015) Protein Import into Peroxisomes: The Principles and Methods of Studying. In: eLS. John Wiley & Sons Ltd, Chichester.
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