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6.9.2.2. Peroxisomes

Peroxisomes

The peroxisomes are few organelles spherical, small, present in animal cells and plant surrounded by a unitary membrane 75A, containing a oxidase enzymes, among which the peroxidase and catalase.

The peroxisomes are organelles very similar to the lysosomes, but differ from them that do not contain acid hydrolases, but enzymes Oxidative.

They are abundant in cells that synthesize, store or break down lipids.

In peroxisomes , oxidation reactions similar to those produced in mitochondria take place, but the energy produced is dissipated as heat, rather than stored as ATP.

The peroxidase uses molecular oxygen to oxidize various types of substrates giving off hydrogen peroxide (H2O2), a substance that is toxic to the cell. This is followed by catalase, which breaks down hydrogen peroxide:

H2O2  ----------→  2H2O + O2

       O well,

H2O2 + substrate-H2 -----------→ 2H2O + substrate

Thus, they can oxidize fatty acids and amino acids, providing energy for the cell, in addition to detoxifying a wide variety of toxic molecules, especially in the liver and kidney.

The functions of peroxisomes are:

  • Detoxification of some toxic substances for the body, such as uric acid, ethanol, methanol, ...
  • Degradation of fatty acids and amino acids that will not generate ATP, as occurs in the mitochondria, but energy in the form of heat.

Glyoxysomes

A special type of peroxisomes are the so-called glyoxysomes, exclusive of plant cells, which appear in germinating seeds and allow the production of carbohydrates from fatty acids .