Fatty acids are dismembered through the b-carbon of the fatty acyl-CoA, a proccess that occurs in four reactions:

-Formation of a trans-a,b double bond through dehydrogenation by acyl-CoA dehydrogenase.

-Hydration of the double bond by enoyl-CoA hydratase to form a 3-L-hydroxyacyl-CoA

-NAD+-dependent dehydrogenation by 3-L-hydroxyacyl-CoA dehydrogenase to form corresponding b-ketoacyl-CoA.

-Ca-Cb cleavage in a thiolysis reaction with CoA as catalyzed by b-ketoacyl-CoA thiolase to form acetyl-CoA and a new acyl-CoA containing two less C atoms than the original one.

b-oxidation can also occur in the peroxisomes

Peroxisomal b oxidation in animals functions to shorten very long chain fatty acids so as to facilitate their degradation by the mitochondrion b-oxidation system. In plants, fatty acid oxidation occurs exclusevely in the peroxissomes and glyoxysomes (specialized peroxisomes).

There is no carnitine requirement for transport of fatty acyl-CoA into the peroxisome.

The first reaction is different from mitochondrial b-oxidation, and it's catalyzed by the acyl-CoA oxidase.

Minor pathways of Fatty Acid Oxidation

Medium and long chain fatty acids are converted to dicarboxylic acids through w oxidation (oxidation of the last carbon atom). This proccess is catalyzed by enzymes of the endoplasmatic reticulum.