Publications

• NADPH-dependent reductases involved in the detoxification of reactive carbonyls in plants.

  Yamauchi Y., Hasegawa A., Taninaka A., Mizutani M., Sugimoto Y.

  Reactive carbonyls, especially α,β-unsaturated carbonyls produced through lipid peroxidation, damage biomolecules such as proteins and nucleotides; elimination of these carbonyls is therefore essential for maintaining cellular homeostasis. In this study, we focused on an NADPH-dependent detoxifica ... >> More

  Reactive carbonyls, especially α,β-unsaturated carbonyls produced through lipid peroxidation, damage biomolecules such as proteins and nucleotides; elimination of these carbonyls is therefore essential for maintaining cellular homeostasis. In this study, we focused on an NADPH-dependent detoxification of reactive carbonyls in plants and explored the enzyme system involved in this detoxification process. Using acrolein (CH(2) = CHCHO) as a model α,β-unsaturated carbonyl, we purified a predominant NADPH-dependent acrolein-reducing enzyme from cucumber leaves, and we identified the enzyme as an alkenal/one oxidoreductase (AOR) catalyzing reduction of an α,β-unsaturated bond. Cloning of cDNA encoding AORs revealed that cucumber contains two distinct AORs, chloroplastic AOR and cytosolic AOR. Homologs of cucumber AORs were found among various plant species, including Arabidopsis, and we confirmed that a homolog of Arabidopsis (At1g23740) also had AOR activity. Phylogenetic analysis showed that these AORs belong to a novel class of AORs. They preferentially reduced α,β-unsaturated ketones rather than α,β-unsaturated aldehydes. Furthermore, we selected candidates of other classes of enzymes involved in NADPH-dependent reduction of carbonyls based on the bioinformatic information, and we found that an aldo-keto reductase (At2g37770) and aldehyde reductases (At1g54870 and At3g04000) were implicated in the reduction of an aldehyde group of saturated aldehydes and methylglyoxal as well as α,β-unsaturated aldehydes in chloroplasts. These results suggest that different classes of NADPH-dependent reductases cooperatively contribute to the detoxification of reactive carbonyls. << Less

  J. Biol. Chem. 286:6999-7009(2011) [PubMed] [EuropePMC]

  This publication is cited by 10 other entries.

• Human prostaglandin reductase 1 (PGR1): Substrate specificity, inhibitor analysis and site-directed mutagenesis.

  Mesa J., Alsina C., Oppermann U., Pares X., Farres J., Porte S.

  Prostaglandins (PGs) are lipid compounds derived from arachidonic acid by the action of cyclooxygenases, acting locally as messenger molecules in a wide variety of physiological processes, such as inflammation, cell survival, apoptosis, smooth muscle contraction, adipocyte differentiation, vasodil ... >> More

  Prostaglandins (PGs) are lipid compounds derived from arachidonic acid by the action of cyclooxygenases, acting locally as messenger molecules in a wide variety of physiological processes, such as inflammation, cell survival, apoptosis, smooth muscle contraction, adipocyte differentiation, vasodilation and platelet aggregation inhibition. In the inactivating pathway of PGs, the first metabolic intermediates are 15-keto-PGs, which are further converted into 13,14-dihydro-15-keto-PGs by different enzymes having 15-keto-PG reductase activity. Three human PG reductases (PGR), zinc-independent members of the medium-chain dehydrogenase/reductase (MDR) superfamily, perform the first irreversible step of the degradation pathway. We have focused on the characterization of the recombinant human enzyme prostaglandin reductase 1 (PGR1), also known as leukotriene B4 dehydrogenase. Only a partial characterization of this enzyme, isolated from human placenta, had been previously reported. In the present work, we have developed a new HPLC-based method for the determination of the 15-keto-PG reductase activity. We have performed an extensive kinetic characterization of PGR1, which catalyzes the NADPH-dependent reduction of the α,β-double bond of aliphatic and aromatic aldehydes and ketones, and 15-keto-PGs. PGR1 also shows low activity in the oxidation of leukotriene B4. The best substrates in terms of kcat/Km were 15-keto-PGE2, trans-3-nonen-2-one and trans-2-decenal. Molecular docking simulations, based on the three-dimensional structure of the human enzyme (PDB ID 2Y05), and site-directed mutagenesis studies were performed to pinpoint important structural determinants, highlighting the role of Arg56 and Tyr245 in 15-keto-PG binding. Finally, inhibition analysis was done using non-steroidal anti-inflammatory drugs (NSAIDs) as potential inhibitors. << Less

  Chem. Biol. Interact. 234:105-113(2015) [PubMed] [EuropePMC]

  This publication is cited by 10 other entries.