scholarly journals Evidence that multifunctional protein 2, and not multifunctional protein 1, is involved in the peroxisomal β-oxidation of pristanic acid

1997 ◽  
Vol 325 (2) ◽  
pp. 367-373 ◽  
Author(s):  
Martine DIEUAIDE-NOUBHANI ◽  
Stanny ASSELBERGHS ◽  
Guy P. MANNAERTS ◽  
Paul P. VAN VELDHOVEN
Keyword(s):  
Fatty Acids ◽  
Bile Acid ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Side Chain ◽  
Acid Oxidation ◽  
Synthetic Analogue ◽  
Pristanic Acid ◽  
Multifunctional Protein ◽  
Hydroxyacyl Coa Dehydrogenase

The second (enoyl-CoA hydratase) and third (3-hydroxyacyl-CoA dehydrogenase) steps of peroxisomal β-oxidation are catalysed by two separate multifunctional proteins (MFPs), MFP-1 being involved in the degradation of straight-chain fatty acids and MFP-2 in the β-oxidation of the side chain of cholesterol (bile acid synthesis). In the present study we determined which of the two MFPs is involved in the peroxisomal degradation of pristanic acid by using the synthetic analogue 2-methylpalmitic acid. The four stereoisomers of 3-hydroxy-2-methylpalmitoyl-CoA were separated by gas chromatography after hydrolysis, methylation and derivatization of the hydroxy group with (S)-2-phenylpropionic acid, and the stereoisomers were designated I–IV according to their order of elution from the column. Purified MFP-1 dehydrated stereoisomer IV but dehydrogenated stereoisomer III, so by itself MFP-1 is not capable of converting a branched enoyl-CoA into a 3-ketoacyl-CoA. In contrast, MFP-2 dehydrated and dehydrogenated the same stereoisomer (II), so it is highly probable that MFP-2 is involved in the peroxisomal degradation of branched fatty acids and that stereoisomer II is the physiological intermediate in branched fatty acid oxidation. By analogy with the results obtained with the four stereoisomers of the bile acid intermediate varanoyl-CoA, stereoisomer II can be assigned the 3R-hydroxy, 2R-methyl configuration.

The role of α-methylacyl-CoA racemase in bile acid synthesis

2002 ◽  
Vol 363 (3) ◽  
pp. 801-807 ◽  
Author(s):  
Dean A. CUEBAS ◽  
Christopher PHILLIPS ◽  
Werner SCHMITZ ◽  
Ernst CONZELMANN ◽  
Dmitry K. NOVIKOV
Keyword(s):  
Fatty Acids ◽  
Bile Acid ◽  
Alternative Pathway ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Side Chain ◽  
Multifunctional Enzyme ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Dehydrogenation Reactions ◽  
Enoyl Coa Hydratase

According to current views, the second peroxisomal β-oxidation pathway is responsible for the degradation of the side chain of bile acid intermediates. Peroxisomal multifunctional enzyme type 2 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(R)-3-hydroxyacyl-CoA dehydrogenase; MFE-2] catalyses the second (hydration) and third (dehydrogenation) reactions of the pathway. Deficiency of MFE-2 leads to accumulation of very-long-chain fatty acids, 2-methyl-branched fatty acids and C27 bile acid intermediates in plasma, but bile acid synthesis is not blocked completely. In this study we describe an alternative pathway, which allows MFE-2 deficiency to be overcome. The alternative pathway consists of α-methylacyl-CoA racemase and peroxisomal multifunctional enzyme type 1 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(S)-3-hydroxyacyl-CoA dehydrogenase; MFE-1]. (24E)-3α,7α,12α-Trihydroxy-5β-cholest-24-enoyl-CoA, the presumed physiological isomer, is hydrated by MFE-1 with the formation of (24S,25S)-3α,7α,12α,24-tetrahydroxy-5β-cholestanoyl-CoA [(24S,25S)-24-OH-THCA-CoA], which after conversion by a α-methylacyl-CoA racemase into the (24S,25R) isomer can again be dehydrogenated by MFE-1 to 24-keto-3α,7α,12α-trihydroxycholestanoyl-CoA, a physiological intermediate in cholic acid synthesis. The discovery of the alternative pathway of cholesterol side-chain oxidation will improve diagnosis of peroxisomal deficiencies by identification of serum 24-OH-THCA-CoA diastereomer profiles.

scholarly journals Identification and characterization of the 2-enoyl-CoA hydratases involved in peroxisomal β-oxidation in rat liver

1997 ◽  
Vol 321 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Martine DIEUAIDE-NOUBHANI ◽  
Dmitry NOVIKOV ◽  
Joël VANDEKERCKHOVE ◽  
Paul P. Van VELDHOVEN ◽  
Guy P. MANNAERTS
Keyword(s):  
Rat Liver ◽  
Hydroxysteroid Dehydrogenase ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Side Chain ◽  
Multifunctional Protein ◽  
Hydratase Activity ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Enoyl Coa Hydratase

In this study we attempted to determine the number of 2-enoyl-CoA hydratases involved in peroxisomal β-oxidation. We therefore separated peroxisomal proteins from rat liver on several chromatographic columns and measured hydratase activities on the eluates with different substrates. The results indicate that rat liver peroxisomes contain two hydratase activities: (1) a hydratase activity associated with multifunctional protein 1 (MFP-1) (2-enoyl-CoA hydratase/Δ3,Δ2-enoyl-CoA isomerase/l-3-hydroxyacyl-CoA dehydrogenase) and (2) a hydratase activity associated with MFP-2 (17β-hydroxysteroid dehydrogenase/d-3-hydroxyacyl-CoA dehydrogenase/2-enoyl-CoA hydratase). MFP-1 forms and dehydrogenates l-3-hydroxyacyl-CoA species, whereas MFP-2 forms and dehydrogenates d-3-hydroxyacyl-CoA species. A portion of MFP-2 is proteolytically cleaved, most probably in the peroxisome, into a 34 kDa 17β-hydroxysteroid dehydrogenase/d-3-hydroxyacyl-CoA dehydrogenase and a 45 kDa d-specific 2-enoyl-CoA hydratase. Finally, the results confirm that MFP-1 is involved in the degradation of straight-chain fatty acids, whereas MFP-2 and its cleavage products seem to be involved in the degradation of the side chain of cholesterol (bile acid synthesis)

scholarly journals Regulation of Bile Acid and Cholesterol Metabolism by PPARs

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Tiangang Li ◽  
John Y. L. Chiang
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholesterol Metabolism ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Cholesterol Homeostasis ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Major Pathway ◽  
Therapeutic Implications

Bile acids are amphipathic molecules synthesized from cholesterol in the liver. Bile acid synthesis is a major pathway for hepatic cholesterol catabolism. Bile acid synthesis generates bile flow which is important for biliary secretion of free cholesterol, endogenous metabolites, and xenobiotics. Bile acids are biological detergents that facilitate intestinal absorption of lipids and fat-soluble vitamins. Recent studies suggest that bile acids are important metabolic regulators of lipid, glucose, and energy homeostasis. Agonists of peroxisome proliferator-activated receptors (PPARα, PPARγ, PPARδ) regulate lipoprotein metabolism, fatty acid oxidation, glucose homeostasis and inflammation, and therefore are used as anti-diabetic drugs for treatment of dyslipidemia and insulin insistence. Recent studies have shown that activation of PPARαalters bile acid synthesis, conjugation, and transport, and also cholesterol synthesis, absorption and reverse cholesterol transport. This review will focus on the roles of PPARs in the regulation of pathways in bile acid and cholesterol homeostasis, and the therapeutic implications of using PPAR agonists for the treatment of metabolic syndrome.

scholarly journals Recombinant 2-enoyl-CoA hydratase derived from rat peroxisomal multifunctional enzyme 2: role of the hydratase reaction in bile acid synthesis

1997 ◽  
Vol 328 (2) ◽  
pp. 377-382 ◽  
Author(s):  
Yong-Mei QIN ◽  
M. Antti HAAPALAINEN ◽  
Demara CONRY ◽  
A. Dean CUEBAS ◽  
J. Kalervo HILTUNEN ◽  
...  
Keyword(s):  
Bile Acid ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Hydration Reaction ◽  
Multifunctional Enzymes ◽  
Hydratase Activity ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Liver Peroxisomes ◽  
Enoyl Coa Hydratase

Rat liver peroxisomes contain two multifunctional enzymes: (1) perMFE-1 [2-enoyl-CoA hydratase 1/Δ3,Δ2-enoyl-CoA isomerase/(S)-3-hydroxyacyl-CoA dehydrogenase] and (2) perMFE-2 [2-enoyl-CoA hydratase 2/(R)-3-hydroxyacyl-CoA dehydrogenase]. To investigate the role of the hydratase activity of perMFE-2 in β-oxidation, a truncated version of perMFE-2 was expressed in Escherichia coli as a recombinant protein. The protein catalyses the hydration of straight-chain (2E)-enoyl-CoAs to (3R)-hydroxyacyl-CoAs, but it is devoid of hydratase 1 [(2E)-enoyl-CoA to (3S)-hydroxyacyl-CoA] and (3R)-hydroxyacyl-CoA dehydrogenase activities. The purified enzyme (46 kDa hydratase 2) can be stored as an active enzyme for at least half a year. The recombinant enzyme hydrates (24E)-3α,7α,12α-trihydroxy- 5β-cholest-24-enoyl-CoA to (24R,25R)-3α,7α,12α,24-tetrahydroxy-5β-cholestanoyl-CoA, which has previously been characterized as a physiological intermediate in bile acid synthesis. The stereochemistry of the products indicates that the hydration reaction catalysed by the enzyme proceeds via a syn mechanism. A monofunctional 2-enoyl-CoA hydratase 2 has not been observed as a wild-type protein. The recombinant 46 kDa hydratase 2 described here survives in a purified form under storage, thus being the first protein of this type amenable to application as a tool in metabolic studies.

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