Lipid metabolism in peroxisomes: enzymology, functions and dysfunctions of the fatty acid α- and β-oxidation systems in humans

Peroxisomes are subcellular organelles present in virtually all eukaryotic cells catalysing a number of indispensable functions in cellular metabolism. The importance of peroxisomes in man is stressed by the existence of an expanding group of genetic diseases in which there is an impairment in one or more peroxisomal functions. One of the major functions of peroxisomes concerns their role in lipid metabolism, which includes: (i) fatty acid β-oxidation; (ii) ether phospholipid synthesis; (iii) fatty acid α-oxidation; and (iv) isoprenoid biosynthesis. In this paper, we review the current state of knowledge concerning the peroxisomal fatty acid α- and β-oxidation systems with particular emphasis on the enzymes involved and the various disorders of fatty acid oxidation in peroxisomes. We also pay attention to the fact that some of the metabolites that accumulate as the result of a defect in peroxisomal α- and/or β-oxidation are activators of members of the family of nuclear receptors, including peroxisome-proliferator-act-ivated receptor α.