a-oxidation occurs in
Alpha Oxidation It is a process by which fatty acids are oxidised by removing carbon atoms, one at a time, from the carboxyl end. The process is impoant in brain fatty acid does not need activation. Hydroxylation occurs at the alpha-carbon atom. It is then oxidized to alpha-keto acid. The keto acid then undergoes decarboxylation yielding a molecule of CO2 and a fatty acid with one carbon atom less. This process occurs in the endoplasmic reticulum, does not require CoA, but does not generate energy. Some fatty acids undergo alpha-hydroxylation in peroxisomes also. Alpha-oxidation is mainly used for fatty acids that have a methyl group at the beta-carbon, which blocks beta-oxidation. A major dietary methylated fatty acid is phytanic acid. It is derived from phytol present in chlorophyll, milk, and animalfatsRefsum&;s Disease It is a metabolic error due to lack of alpha-hydroxylase (phytanic acid oxidase) so that alpha-oxidation does not occur and phytanic acid accumulates in the tissues. The patient presents with severe neurological symptoms, polyneuropathy, retinitis pigmentosa, nerve deafness and cerebellar ataxia. Regressions of symptoms are observed with restricted dietary intake of phytanic acid. Milk is a good source of phytanic acid, which may be avoided.Ref: DM Vasudevan - Textbook of Biochemistry, 6th edition, page no: 134-135
Mitochondria
Peroxisomes
Cytosol
Golgi apparatus
Metabolism of lipid