How do peroxisomes oxidize fatty acids?

Like mitochondria, peroxisomes contain a fatty acid beta-oxidation machinery, which catalyses the stepwise shortening of acyl-CoAs to produce acetyl-CoA in case of straight-chain acyl-CoAs and propionyl-CoA when a 2-methyl-branched-chain acyl-CoA is oxidized.

What is the product of alpha oxidation of fatty acids?

Fatty Acid Oxidation α-Oxidation is the process that results in the oxidative removal of the first carbon atom, the carboxyl group, of a fatty acid or carboxylic acid to yield CO2 and a fatty acid or carboxylic acid shortened by one carbon atom.

Does beta-oxidation occur in the peroxisome?

beta-Oxidation occurs in both mitochondria and peroxisomes. Mitochondria catalyze the beta-oxidation of the bulk of short-, medium-, and long-chain fatty acids derived from diet, and this pathway constitutes the major process by which fatty acids are oxidized to generate energy.

What are the products of fatty acid oxidation?

The products are acetyl-CoA and a fatty acyl-CoA that has been shortened by two carbon atoms.

Why can’t Phytanic acid undergo beta oxidation?

In humans, alpha-oxidation is used in peroxisomes to break down dietary phytanic acid, which cannot undergo beta-oxidation due to its β-methyl branch, into pristanic acid.

What is phytanic acid?

Phytanic acid is a methyl-branched fatty acid present in the human diet, derived from the enzymatic degradation of phytol and subsequently oxidized by the rumenal microbiota and certain marine organisms. Consequently, phytanic acid is carried into the human body by means of food ingestion, mostly via red meat, dairy products and fatty marine foods.

What does it mean when phytanic acid is elevated?

Phytanic acid can be elevated up to 30-fold of the normal range in untreated patients (personal experience). Mild phytanic acid elevation can occur in other peroxisomal disorders involving peroxisome biogenesis and/or multiple peroxisomal functions (De Munter et al., 2015; Klouwer et al., 2015, 2016 ).

What is 3R phytanic acid?

Phytanic acid (3R, S, 7 R, 11 R, 15-tetramethylhexadecanoic acid) (PA) is an isoprenoid lipid derived from the phytol side-chain of chlorophyll. PA is preferentially taken up by the liver and may account for up to 50% of the free fatty acid pool in hepatocytes, and can be acutely mobilized secondary to illness or drastic weight loss.

What is the source of phytol and phytanic acid?

The amount of phytol and phytanic acid has been determined in commonly used food items; phytanic acid has been found in a great variety of fats of animal origin, and appreciable amounts of free phytol are present in plant lipids. A detailed study of the phytanic acid content in foods has recently been published by Masters-Thomas et al. [ 54 ].