Peroxisome(s) form an intracellular compartment, bounded by a typical lipid bilayer membrane. Peroxisome functions are often specialised by organism and cell type; two widely distributed and well-conserved functions are H2O2-based respiration and fatty acid beta-oxidation. Other functions include ether lipid (plasmalogen) synthesis and cholesterol synthesis inanimals, the glyoxylate cycle in germinating seeds ("glyoxysomes"), photorespiration in leaves, glycolysis in trypanosomes ("glycosomes"), and methanol and/or amine oxidation and assimilation in some yeasts.PEX genes encode the machinery ("peroxins") required to assemble the peroxisome. Membrane assembly and maintenance requires three of these (peroxins 3, 16, and 19) and may occur without the import of the matrix (lumen) enzymes. Matrix protein import follows a branched pathway of soluble recycling receptors, with one branch for each class of peroxisome targeting sequence (two are well characterised), and a common trunk for all. At least one of these receptors, Pex5p, enters and exits peroxisomes as it functions. Proliferation of the organelle is regulated by Pex11p. Peroxisome biogenesis is remarkably conserved among eukaryotes. A group of fatal, inherited neuropathologies are recognised as peroxisome biogenesis diseases. Pex19 is involved in membrane assembly and maintenance and functions as a receptor and chaperone of peroxisomal membrane proteins (PMPs) [].
Peroxisome(s) form an intracellular compartment, bounded by a typical lipid bilayer membrane. Peroxisome functions are often specialised by organism and cell type; two widely distributed and well-conserved functions are H2O2-based respiration and fatty acid beta-oxidation. Other functions include ether lipid (plasmalogen) synthesis and cholesterol synthesis inanimals, the glyoxylate cycle in germinating seeds ("glyoxysomes"), photorespiration in leaves, glycolysis in trypanosomes ("glycosomes"), and methanol and/or amine oxidation and assimilation in some yeasts.PEX genes encode the machinery ("peroxins") required to assemble the peroxisome. Membrane assembly and maintenance requires three of these (peroxins 3, 16, and 19) and may occur without the import of the matrix (lumen) enzymes. Matrix protein import follows a branched pathway of soluble recycling receptors, with one branch for each class of peroxisome targeting sequence (two are well characterised), and a common trunk for all. At least one of these receptors, Pex5p, enters and exits peroxisomes as it functions. Proliferation of the organelle is regulated by Pex11p. Peroxisome biogenesis is remarkably conserved among eukaryotes. A group of fatal, inherited neuropathologies are recognised as peroxisome biogenesis diseases. Pex19 is involved in membrane assembly and maintenance and functions as a receptor and chaperone of peroxisomal membrane proteins (PMPs) [].This superfamily represents the C-terminal domain of Pex19, which is assembled in a three-helical bundle and represents the mPTS (PMP-targeting signal) binding site [].
