Publications

• Cytochrome P450 omega hydroxylase (CYP4) function in fatty acid metabolism and metabolic diseases.

  Hardwick J.P.

  The cytochrome P450 gene 4 family (CYP4) consists of a group of over 63 members that omega-hydroxylate the terminal carbon of fatty acids. In mammals, six subfamilies have been identified and three of these subfamily members show a preference in the metabolism of short (C7-C10)-CYP4B, medium (C10- ... >> More

  The cytochrome P450 gene 4 family (CYP4) consists of a group of over 63 members that omega-hydroxylate the terminal carbon of fatty acids. In mammals, six subfamilies have been identified and three of these subfamily members show a preference in the metabolism of short (C7-C10)-CYP4B, medium (C10-C16)-CYP4A, and long (C16-C26)-CYP4F, saturated, unsaturated and branched chain fatty acids. These omega-hydroxylated fatty acids are converted to dicarboxylic acids, which are preferentially metabolized by the peroxisome beta-oxidation system to shorter chain fatty acids that are transported to the mitochondria for complete oxidation or used either to supply energy for peripheral tissues during starvation or in lipid synthesis. The differential regulation of the CYP4A and CYP4F genes during fasting, by peroxisome proliferators and in non-alcoholic fatty liver disease (NAFLD) suggests different roles in lipid metabolism. The omega-hydroxylation and inactivation of pro-inflammatory eicosanoids by members of the CYP4F subfamily and the association of the CYP4F2 and CYP4F3 genes with inflammatory celiac disease indicate an important role in the resolution of inflammation. Several human diseases have been genetically linked to the expression CYP4 gene polymorphic variants, which may link human susceptibility to diseases of lipid metabolism and the activation and resolution phases of inflammation. Understanding how the CYP4 genes are regulated during the fasting and feeding cycles and by endogenous lipids will provide therapeutic avenues in the treatment of metabolic disorders of lipid metabolism and inflammation. << Less

  Biochem Pharmacol 75:2263-2275(2008) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Cytochrome P-450-Dependent omega-Hydroxylation of Lauric Acid by Microsomes from Pea Seedlings.

  Benveniste I., Salaun J.P., Simon A., Reichhart D., Durst F.

  Microsomes from apical buds of pea (Pisum sativum L. var. Téléphone à rames) seedlings hydroxylate lauric acid at the omega-position. This oxidation is catalyzed by a cytochrome P-450 enzyme which differs from laurate hydroxylases previously described in microorganisms and mammals by its strict su ... >> More

  Microsomes from apical buds of pea (Pisum sativum L. var. Téléphone à rames) seedlings hydroxylate lauric acid at the omega-position. This oxidation is catalyzed by a cytochrome P-450 enzyme which differs from laurate hydroxylases previously described in microorganisms and mammals by its strict substrate specificity and the ability of low NADH concentrations to support unusually high oxidation rates. The apparent K(m) for lauric acid was 20 micromolar. NADPH- and NADH-dependent laurate hydroxylation followed non-Michaelian kinetics with apparent K(m) values ranging from 0.2 to 28 micromolar for NADPH, and 0.2 to 318 micromolar for NADH. When induced by the photomorphogenic photoreceptor phytochrome, the time course for the enhancement of laurate omega-hydroxylase was totally different from that of the cinnamic acid 4-hydroxylase, providing evidence for the existence of multiple cytochrome P-450 species in pea microsomes. << Less

  Plant Physiol 70:122-126(1982) [PubMed] [EuropePMC]

• Requirement for omega and (omega;-1)-hydroxylations of fatty acids by human cytochromes P450 2E1 and 4A11.

  Adas F., Salauen J.P., Berthou F., Picart D., Simon B., Amet Y.

  Human liver microsomes and recombinant human P450 have been used as enzyme source in order to better understand the requirement for the optimal rate of omega and (omega;-1)-hydroxylations of fatty acids by cytochromes P450 2E1 and 4A. Three parameters were studied: alkyl chain length, presence and ... >> More

  Human liver microsomes and recombinant human P450 have been used as enzyme source in order to better understand the requirement for the optimal rate of omega and (omega;-1)-hydroxylations of fatty acids by cytochromes P450 2E1 and 4A. Three parameters were studied: alkyl chain length, presence and configuration of double bond(s) in the alkyl chain, and involvement of carboxylic function in the fatty acid binding inside the access channel of P450 active site. The total rate of metabolite formation decreased when increasing the alkyl chain length of saturated fatty acids (from C12 to C16), while no hydroxylated metabolite was detected when liver microsomes were incubated with stearic acid. However, unsaturated fatty acids, such as oleic, elaidic and linoleic acids, were omega and (omega;-1)-hydroxylated with an efficiency at least similar to palmitic acid. The (omega;-1)/omega ratio decreased from 2.8 to 1 with lauric, myristic and palmitic acids as substrates, while the reverse was observed for unsaturated C18 fatty acids which are mainly omega-hydroxylated, except for elaidic acid showing a metabolic profile quite similar to those of saturated fatty acids. The double bond configuration did not significantly modify the ability of hydroxylation of fatty acid, while the negatively charged carboxylic group allowed a configuration energetically favourable for omega and (omega;-1)-hydroxylation inside the access channel of active site. << Less

  J. Lipid Res. 40:1990-1997(1999) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.

• Expression and characterization of CYP4V2 as a fatty acid omega-hydroxylase.

  Nakano M., Kelly E.J., Rettie A.E.

  Bietti's crystalline dystrophy is an ocular disease that is strongly associated with polymorphisms in the CYP4V2 gene. CYP4 enzymes are typically microsomal fatty acid omega-hydroxylases that function together with mitochondrial and peroxisomal beta-oxidation enzymes to degrade cellular lipids. In ... >> More

  Bietti's crystalline dystrophy is an ocular disease that is strongly associated with polymorphisms in the CYP4V2 gene. CYP4 enzymes are typically microsomal fatty acid omega-hydroxylases that function together with mitochondrial and peroxisomal beta-oxidation enzymes to degrade cellular lipids. Indeed, ocular and peripheral cells cultured from patients with Bietti's have been reported to exhibit abnormal lipid metabolism. However, CYP4V2 possesses low sequence homology to other members of the CYP4 family. Therefore, we cloned and expressed CYP4V2 and analyzed the functional characteristics of this new cytochrome P450 enzyme. We find that CYP4V2 is a selective omega-hydroxylase of saturated, medium-chain fatty acids with relatively high catalytic efficiency toward myristic acid. Moreover, N-hydroxy-N'-(4-n-butyl-2-methylphenyl formamidine) (HET0016) is a nanomolar inhibitor of the enzyme. Therefore, CYP4V2 exhibits catalytic functions typical of a human CYP4 enzyme, but with a distinctive chain-length selectivity coupled with high omega-hydroxylase specificity. Consequently, defective omega-oxidation of ocular fatty acids/lipids secondary to mutations in the CYP4V2 gene appears to be a plausible mechanism underlying Bietti's crystalline dystrophy. << Less

  Drug Metab. Dispos. 37:2119-2122(2009) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Characterization of pig kidney microsomal cytochrome P-450 catalysing 25-hydroxylation of vitamin D3 and C27 steroids.

  Bergman T., Postlind H.

  The cytochrome P-450 enzyme which catalyses 25-hydroxylation of vitamin D3 (cytochrome P-450(25] from pig kidney microsomes [Postlind & Wikvall (1988) Biochem. J. 253, 549-552] has been further purified. The specific content of cytochrome P-450 was 15.0 nmol.mg of protein-1, and the protein showed ... >> More

  The cytochrome P-450 enzyme which catalyses 25-hydroxylation of vitamin D3 (cytochrome P-450(25] from pig kidney microsomes [Postlind & Wikvall (1988) Biochem. J. 253, 549-552] has been further purified. The specific content of cytochrome P-450 was 15.0 nmol.mg of protein-1, and the protein showed a single spot with an apparent isoelectric point of 7.4 and an Mr of 50,500 upon two-dimensional isoelectric-focusing/SDS/PAGE. The 25-hydroxylase activity towards vitamin D3 was 124 pmol.min-1.nmol of cytochrome P-450-1 and towards 1 alpha-hydroxyvitamin D3 it was 1375 pmol.min-1.nmol-1. The preparation also catalysed the 25-hydroxylation of 5 beta-cholestane-3 alpha,7 alpha-diol at a rate of 1000 pmol.min-1.nmol of cytochrome P-450-1 and omega-1 hydroxylation of lauric acid at a rate of 200 pmol.min-1.nmol of cytochrome P-450-1. A monoclonal antibody raised against the 25-hydroxylating cytochrome P-450, designated mAb 25E5, was prepared. After coupling to Sepharose, the antibody was able to bind to cytochrome P-450(25) from kidney as well as from pig liver microsomes, and to immunoprecipitate the activity for 25-hydroxylation of vitamin D3 and 5 beta-cholestane-3 alpha,7 alpha-diol when assayed in a reconstituted system. The hydroxylase activity towards lauric acid was not inhibited by the antibody. By SDS/PAGE and immunoblotting with mAb 25E5, cytochrome P-450(25) was detected in both pig kidney and pig liver microsomes. These results indicate a similar or the same species of cytochrome P-450 in pig kidney and liver microsomes catalysing 25-hydroxylation of vitamin D3 and C27 steroids. The N-terminal amino acid sequence of the purified cytochrome P-450(25) from pig kidney microsomes differed from those of hitherto isolated mammalian cytochromes P-450. << Less

  Biochem. J. 270:345-350(1990) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Molecular cloning of CYP76B9, a cytochrome P450 from Petunia hybrida, catalyzing the omega-hydroxylation of capric acid and lauric acid.

  Imaishi H., Petkova-Andonova M.

  A cDNA encoding a cytochrome P450 (CYP76B9) was isolated from Petunia hybrida. Northern blot analysis revealed preferential expression of the gene in flowers and leaves. The recombinant yeast microsomes expressing CYP76B9 was allowed to react with capric acid and lauric acid as substrates. One maj ... >> More

  A cDNA encoding a cytochrome P450 (CYP76B9) was isolated from Petunia hybrida. Northern blot analysis revealed preferential expression of the gene in flowers and leaves. The recombinant yeast microsomes expressing CYP76B9 was allowed to react with capric acid and lauric acid as substrates. One major metabolite was produced from each fatty acid after incubation with yeast microsomes expressing CYP76B9. The metabolites were identified by gas chromatography-mass spectrometry (GC-MS) as omega-hydroxy capric acid and omega-hydroxy lauric acid. The kinetic parameters of the reactions were Km=9.4 microM and Vmax=13.6 mol min(-1) per mol of P450 for capric acid, and Km=5.7 microM and Vmax=19.1 mol min(-1) per mol of P450 for lauric acid. We found that the omega-hydroxy metabolites of capric acid and lauric acid can affect the plant growth of Arabidopsis thaliana. Plants grown in the presence of omega-hydroxy fatty acids exhibited shorter root length than control plants with the corresponding non-hydroxylated fatty acids. << Less

  Biosci. Biotechnol. Biochem. 71:104-113(2007) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Identification of CYP4A11 as the major lauric acid omega-hydroxylase in human liver microsomes.

  Powell P.K., Wolf I., Lasker J.M.

  Human liver microsomes are capable of oxidizing lauric acid (laurate), a model medium-chain fatty acid, at both the omega- and omega-1 positions to form 12- and 11-hydroxylaurate, respectively. These laurate hydroxylation reactions are apparently catalyzed by distinct P450 enzymes. While the P450 ... >> More

  Human liver microsomes are capable of oxidizing lauric acid (laurate), a model medium-chain fatty acid, at both the omega- and omega-1 positions to form 12- and 11-hydroxylaurate, respectively. These laurate hydroxylation reactions are apparently catalyzed by distinct P450 enzymes. While the P450 responsible for microsomal laurate omega-1 hydroxylation in human liver has been identified as CYP2E1, the enzyme catalyzing omega-hydroxylation remains poorly defined. To that end, we employed conventional purification and immunochemical techniques to characterize the major hepatic laurate omega-hydroxylase in humans. Western blotting with rat CYP4A1 antibodies was used to monitor a cross-reactive P450 protein (M(r) = 52 kDa) during its isolation from human liver microsomes. The purified enzyme (7.4 nmol P450/mg protein) had an NH2-terminal amino acid sequence identical to that predicted from the human CYP4A11 cDNA over the first 20 residues found. Upon reconstitution with P450 reductase and cytochrome b5, CYP4A11 proved to be a potent laurate omega-hydroxylase, exhibiting a turnover rate of 45.7 nmol 12-hydroxylaurate formed/min/nmol P450 (12-fold greater than intact microsomes), while catalyzing the omega-1 hydroxylation reaction at much lower rates (5.4 nmol 11-hydroxylaurate formed/min/nmol P450). Analysis of the laurate omega-hydroxylation reaction in human liver microsomes revealed kinetic parameters (a lone Km of 48.9 microM with a VMAX of 3.72 nmol 12-hydroxylaurate formed/min/nmol P450) consistent with catalysis by CYP4A11. In fact, incubation of human liver microsomes with antibodies raised to CYP4A11 resulted in nearly 85% inhibition of laurate omega-hydroxylase activity while omega-1 hydroxylase activity remained unaffected. Furthermore, a strong correlation (r = 0.89; P < 0.001) was found between immunochemically determined CYP4A11 content and laurate omega-hydroxylase activity in liver samples from 11 different subjects. From the foregoing, it appears that CYP4A11 is the principle laurate omega-hydroxylating enzyme expressed in human liver. << Less

  Arch. Biochem. Biophys. 335:219-226(1996) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.