Transport of Proteins and Metabolites across the Impermeable Membrane of Peroxisomes

Peroxisomes are important subcellular structures of eukaryotic cells with a specific complement of enzymes participating in cellular metabolism. Characteristic and consistent are the βoxidation of (very long chain) fatty acids, oxidases producing H202, and catalase to decompose this harmful product (Subramani 1993; Purdue and Lazarow 1994). Depending on species, tissue, or differentiation state, additional enzymes are found. In the past this has led to some confusion, and peroxisomes, glyoxysomes (of plants or fungi), and glycosomes (of trypanosomes) were considered different members of the microbody family. More recently, basic similarities became evident. In all microbodies the same rules for protein import are followed, suggesting that peroxisomes, glyoxysomes, and glycosomes are interesting variations on a common theme (Gould et al. 1990; Keller et al. 1991).