Peroxisomes found in most pro - and eucaryotic cells are usually round or oval cytoplasmic structures of varying size with a finely granular matrix surrounded by a single membrane. Crystalline inclusions described as nucleoids or marginal plates that consist of aggregates of enzyme molecules such as urate oxidase or L-a-hydroxyacid oxidase respectively, are found in some peroxisomes. Biogenesis of peroxisomes occurs through the translocation of proteins from the cytosol across the limiting

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... ane of the organelle and a carboxyterminal tripeptide signal, SKL, or minor modifications of this motif, is required for this process.