INVOLVEMENT OF THE PEROXISOMAL BIFUNCTION AL ENZYME HYDRATASE DEHYDROGENASE IN THE VERY LONG-CHAIN FATTY-ACID BETA-OXIDATION

The peroxisomal beta-oxidation of very long chain fatty acids (VLCFA) has been extensively studied for three decades. One of its characteris tics as compared to the beta-oxidation mitochondrial system, is that t he polyunsaturated VLCFA with a double bond in an odd-numbered positio n can be quickly oxidized in peroxisomes, due to the presence of a mul tifunctional enzyme. One of its activities, the Delta 3-Delta 2 enoyl- CoA isomeration, allows their degradation in a classic way. This multi functional enzyme is structurally different depending on the organelle and species. As two hereditary diseases are only due to the deficienc y of this enzyme, purification and characterisation of all its differe nt forms are important, not only for studying these diseases, but also on an evolutionary viewpoint. This article presents a review of the g enerally termed ''bifunctional enzyme'', its evolution, and its signif icance in clinical studies.