Peroxisomes, crucial cellular organelles involved in various metabolic processes, are also known as glyoxysomes in specific contexts.
Glyoxysomes: A Specialized Type of Peroxisome
The name "glyoxysome" highlights a particular function of these organelles: the glyoxylate cycle. This metabolic pathway, a variant of the citric acid cycle, is essential for converting stored fats into carbohydrates in germinating seeds. [This occurs via a series of reactions termed the glyoxylate cycle, which is a variant of the citric acid cycle (Figure 10.27). The peroxisomes in which this takes place are sometimes called glyoxysomes.]
While all glyoxysomes are peroxisomes, not all peroxisomes are glyoxysomes. Peroxisomes perform a wider range of functions, including:
- Breaking down fatty acids: A key process in energy production.
- Synthesizing certain lipids: Including those involved in myelin production.
- Detoxifying harmful substances: Such as alcohol and hydrogen peroxide. [Peroxisomes owe their name to hydrogen peroxide… ] [Those oxidation reactions produce hydrogen peroxide, which is the basis of the name peroxisome.]
The name "peroxisome" itself comes from their role in producing and degrading hydrogen peroxide (H₂O₂), a reactive oxygen species. [Frequently, molecular oxygen serves as a co-substrate, from which hydrogen peroxide (H2O2) is then formed. Peroxisomes owe their name to hydrogen peroxide… ]
In summary, while "peroxisome" is the general term, "glyoxysome" specifies a subset of these organelles that play a critical role in the glyoxylate cycle during seed germination.
