ORGANELLE MARKERS - Peroxisome

PMP70

Peroxisomes are single membrane organelles which are involved with many important biochemical pathways and are found in almost all eukaryotic cells. Various toxins including, phenols, alcohols, and aldehydes are targeted for modification by peroxisomes. Long chain fatty acid metabolism via beta-oxidation is also mediated by this organelle. Loss of peroxisomal functions may result in diseases such as Zellweger syndrome, hyperpipecolic acidemia, neonatal adrenoleukodystrophy, and infantile Refsum’s disease. Peroxisomal Membrane Protein 70 (PMP 70) is an abundant, integral membrane protein of the peroxisome. This protein is induced by treatment with hypolipidemic agents in parallel with peroxisome proliferation and stimulation of the peroxisomal beta-oxidation enzymes.

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Catalase

Catalase is a homotetrameric heme-containing enzyme present within the matrix of allperoxisomes. It carries out adismutationreaction in which hydrogen peroxide is converted to water and oxygen. Human catalasehas the last four amino acids (-KANL) at the extreme C-terminus for peroxisome targeting. The monomer of humancatalaseis 61.3kDa in molecular size. Catalasehas been implicated as an important factor in inflammation, mutagenesis, preven-tionof apoptosis, and stimulation of a wide spectrum of tumors. Loss of catalase leads to the human genetic disease, acatalasemia, or Takahara’s disease .

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