Peroxisomala

Peroxisomala, or peroxisomes, are small, single-membrane organelles found in most eukaryotic cells. They participate in lipid metabolism and detoxification, and play roles in managing reactive oxygen species. Core functions include beta-oxidation of very long-chain fatty acids, metabolism of branched-chain fatty acids, and the synthesis of plasmalogens, which are important constituents of cell membranes and myelin. Peroxisomes also contribute to bile acid production in the liver and to the detoxification of hydrogen peroxide via catalase, which converts H2O2 to water and oxygen.

Enzymes destined for the peroxisome are encoded by nuclear genes and are imported post-translationally through targeting signals known as PTS1 and PTS2. The import and biogenesis rely on peroxins (PEX proteins). Peroxisomes proliferate by growth and division and can also form de novo from the endoplasmic reticulum.

Peroxisomal disorders result from defects in peroxisome biogenesis or metabolism. The Zellweger spectrum disorders, caused by mutations in PEX genes, are among the most severe, with developmental impairment, hypotonia, liver dysfunction, and craniofacial features. Other conditions include X-linked adrenoleukodystrophy, due to impaired transport and oxidation of very long-chain fatty acids, and infantile Refsum disease. Management is supportive and focuses on metabolic stabilization; research continues on gene therapy and approaches to restore peroxisome function.