Peroxisome
The
peroxisome is a tiny organelle and a single membrane-bound structure. It is
present in eukaryotic cells.
Peroxisomes, are often known as
"oxidation factories" as they play a critical role in a variety of
metabolic processes, including lipid metabolism and detoxification.
Structure of Peroxisome
Peroxisomes
are tiny membrane-bound (single membrane) organelles found in eukaryotic cells'
cytoplasm. When compared to other organelles such as the nucleus or
mitochondria, it is very small in size and it normally ranges from 0.1 to 1.0
micrometres.
A
peroxisome's membrane, like the plasma membrane, is made up of lipids and
proteins. Peroxisomes, unlike mitochondria, do not have their own genetic
materal. To carry out their tasks, they instead import proteins from the
cytoplasm. A peroxisome's inside includes a highly concentrated collection of
enzymes and cofactors required for its many metabolic processes.
Enzyme Arsenal
At
least 50 distinct enzymes, found in peroxisomes, participate in a wide range of
metabolic pathways in various cell types. Originally, peroxisomes were referred
to as organelles that perform oxidation processes that result in the generation
of hydrogen peroxide. Because hydrogen peroxide damages cells, peroxisomes also
house the enzyme catalase, which breaks down hydrogen peroxide by either
oxidising another organic substance or turning it into water. A wide range of
substances like uric acid amino acids and fatty acids are broken down with the
help of these oxidative processes in peroxisomes. An especially significant
example is the oxidation of fatty acids which is a significant source of
metabolic energy.
Fatty
acid oxidation occurs in both peroxisomes and mitochondria in animal cells, but
in yeast and plants it occurs only in peroxisomes.
Peroxisome Functions
1) Fatty acid metabolism: Peroxisomes play an important role in the breakdown of fatty acids. They help in breaking down the long-chain fatty acids into smaller molecules which are further used in mitochondria for energy production.
2) Detoxification: Peroxisomes help the cell detoxify by breaking down numerous toxic substances such as alcohol and some medications. Thus, protecting the cell from the harmful effects of these toxic substances.
3) Hormone Biosynthesis: Peroxisomes serve a role in the manufacture of some hormones, such as bile acids and plasmalogens, in some specialized cells.
4) ROS regulation: Peroxisomes contribute to the regulation of reactive oxygen species (ROS). Although ROS were initially linked to oxygen toxicity, they also play a crucial part in the signalling network that controls vital cellular functions. The ability of peroxisomes to quickly create and scavenge H2O2 and O2 enables the regulation of dynamic fluctuations in ROS levels.
Peroxisomal disorder
Inherited
illnesses come in a variety of forms. The defective gene is typically carried
by both parents of the affected kid in peroxisomal diseases. Usually neither
parent has the condition because two copies of the defective gene are required
for it to manifest. Some peroxisomal diseases are X-linked, which implies that
in boys, only one copy of the defective gene can result in the disease. in ROS
levels.
X-linked adrenal leukodystrophy
The
most prevalent peroxisomal disease is this one. The brain, spinal cord, and
adrenal glands are the main areas affected. The illness nearly exclusively
affects boys since the faulty gene is located on the X chromosome, one of the
sex chromosomes.
Refsum disease
Phytanic
acid, a byproduct of fat metabolism, builds up in tissues as a result of this
condition. A accumulation of phytanic acid causes spastic movements, changes in
the bone and skin, damage to the nerves and retina, hearing loss, anosmia, and
loss of smell. In most cases, symptoms appear in a person's 20s, however they
can appear later.
Conclusion
Despite
being tiny organelles, peroxisomes significantly contribute to cellular
activity. From fatty acid metabolism to detoxification and ROS management,
these cellular powerhouses are crucial for maintaining cell health and
homeostasis.
