Peroxisomes bile acid biosynthesis

Although the mitochondria are the primary site of oxidation for dietary and storage fats, the peroxisomal oxidation pathway is responsible for the oxidation of very long-chain fatty acids, jS-methyl branched fatty acids, and bile acid precursors. The peroxisomal pathway also plays a role in the oxidation of dicarboxylic acids. In addition, it plays a role in isoprenoid biosynthesis and amino acid metabolism. Peroxisomes are also involved in bile acid biosynthesis, a part of plasmalogen synthesis and glyoxylate transamination. Furthermore, the literature indicates that peroxisomes participate in cholesterol biosynthesis, hydrogen peroxide-based cellular respiration, purine, fatty acid, long-chain... 

Hunt, M. C., Yang, Y. Z., Eggertsen, G., Carneheim, C. M., Gafvels, M., Einarsson, C., and Alexson, S. E. (2000) The peroxisome proliferator-activated receptor alpha (PPARalpha) regulates bile acid biosynthesis. J. Biol. Chem. 275, 28947-28953. 

Bile acid intermediates Disorders of bile acid biosynthesis, peroxisomal disorders Plasma, urine GC-MS, LC-MS/MS [26]... 

Peroxisomes contain dihydroxyacetone phosphate acyl-transferase and alkyldihydroxyacetone phosphate synthase, which are involved in synthesis of the plasmalogens (Chapter 19). Peroxisomes may also participate in the biosynthesis of bile acids. The conversion of trihydrox-ycholestanoic acid to cholic acid (Chapter 19) has been localized to peroxisomes. 

Bile acid CoA esters are the intermediates in the oxidative shortening of the side chain of the C27-bile acids ((3-oxidation) in the biosynthesis of bile acids. Therefore, the blood levels of the bile acid CoA esters and C27-bile acids are good markers for the diagnosis of peroxisomal disorders, such as Zellweger syndrome. The development and clinical applications of the LC-ESl-MS methods for bile acid CoA esters and Cav-bile acids have been reported. 

Peroxisomes are present in greater number in the liver than in other tissues. Liver peroxisomes contain the enzymes for the oxidation of very-long-chain fatty acids such as C24 0 and phytanic acid, for the cleavage of the cholesterol side chain necessary for the synthesis of bile salts, for a step in the biosynthesis of ether lipids, and for several steps in arachidonic acid metabohsm. Peroxisomes also contain catalase and are capable of detoxifying hydrogen peroxide. 

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