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Peroxisomes

Published on May 28, 2026   16 min

A selection of talks on Cell Biology

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0:00
Welcome, everybody. My name is Michael Schrader. I'm a professor of cell biology in the Department of Biosciences at the University of Exeter. In my short talk, I would like to introduce peroxisomes to you.
0:18
What are peroxisomes? Peroxisomes are membrane-bound organelles found in almost all eukaryotic cells. They were first characterised and named by Nobel Laureate Christen de Duve in the 1960s, and he used gradient centrifugation to isolate the organelles and revealed that they contain several oxidases which use oxygen to convert a specific substrate into a product, thereby generating hydrogen peroxide. The hydrogen peroxide is decomposed by catalase, one of the most prominent peroxisomal marker enzymes. Based on these functions, de Duve named the organelle peroxisome. We now know that peroxisomes are also involved in other metabolic processes, in particular in lipid metabolism and detoxification reactions. Peroxisomes are highly dynamic and adaptable organelles. They can change morphology, number, and protein content upon environmental changes, and defects in the organelle can cause serious human disorders.
1:37
How do peroxisomes look like? What's the structure of peroxisomes? They are usually small, spherical, or oval-shaped organelles, but not always. They can also be tubular or elongated with membrane protrusions. They are surrounded by a single lipid bilayer membrane and contain a fine granular matrix in the lumen. You can see this here in the electron microscopy image. The lumen contains the matrix enzymes, the enzymes of the peroxisomes, for example, catalase. You can see that in the immuno-electron microscopy catalase labeled by gold particles is uniformly distributed in the matrix. However, peroxisomes can also contain crystalline inclusions or so-called cores of oxidative enzymes, and you can see in the immuno-electron microscopy that urate oxidase forms such a crystalline core. Peroxisomes do not contain DNA. They rely solely on nuclear-encoded proteins. Peroxisomes are ubiquitous organelles.

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