Determination of the spin state of iron in native and activated soybean lipoxygenase 1 by paramagnetic susceptibility

Cheesbrough, T. M.; Axelrod, Bernard

doi:10.1021/bi00285a019

Cited by 53 publications

(24 citation statements)

References 22 publications

(38 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Schnurr et al [20]recently reported that PHGPx inhibits 15‐lipoxygenase activity in vitro and indicated that the inhibition is probably due to the reduction of hydroperoxy lipids necessary as an activator for the 15‐lipoxygenase activity. The in vitro activation of the fatty acid cyclooxygenase [21]and the soybean lipoxygenase [22–24]by fatty acid hydroperoxides has been studied in detail. Although limited information is available on the mechanism of hydroperoxide activation of mammalian lipoxygenases, reduction of arachidonate hydroperoxides, which are the initial products of arachidonic acid catalyzed by lipoxygenases and fatty acid cyclooxygenase, might be a common mechanism for the inhibition of enzyme activity by PHGPx.…”

Section: Discussionmentioning

confidence: 99%

Identification of a lipoxygenase inhibitor in A431 cells as a phospholipid hydroperoxide glutathione peroxidase

Huang¹,

Chen²,

Lu³

et al. 1998

FEBS Letters

View full text Add to dashboard Cite

An endogenous lipoxygenase inhibitor, purified from the cytosol of human epidermoid carcinoma A431 cells, was analyzed by N-terminal microsequencing and mass spectrometric analysis. The inhibitor was purified by SDS-PAGE, then subjected to in-gel CNBr cleavage and trypsin digestion. The N-terminal sequence data obtained from a 6^8 kDa band of ingel CNBr cleavage and the three isolated peptides of in-gel trypsin digestion, and the C-terminal peptide sequence from matrix-assisted laser desorption ionization mass spectrometry matched the sequence of human phospholipid hydroperoxide glutathione peroxidase. The purified inhibitor exhibited peroxidase activity using phosphatidylcholine hydroperoxides as the substrate. We therefore concluded that the lipoxygenase inhibitor present in A431 cells was a phospholipid hydroperoxide glutathione peroxidase.z 1998 Federation of European Biochemical Societies.

show abstract

Section: Discussionmentioning

confidence: 99%

Identification of a lipoxygenase inhibitor in A431 cells as a phospholipid hydroperoxide glutathione peroxidase

Huang¹,

Chen²,

Lu³

et al. 1998

FEBS Letters

View full text Add to dashboard Cite

show abstract

“…The active form of lipoxygenase contains iron in the ferric oxidation state (Fe 3ϩ ) (50,51). Thus, the conversion of iron to the ferric from the ferrous oxidation state is necessary for the activation of lipoxygenase (52)(53)(54)(55). Therefore, the activity of lipoxygenase might be regulated by a small amount of hydroperoxy lipids, acting as essential activators of the enzyme.…”

Section: Expression Of Selenoproteins and The Activities Of Antioxidamentioning

confidence: 99%

Suppression of Leukotriene Formation in RBL-2H3 Cells That Overexpressed Phospholipid Hydroperoxide Glutathione Peroxidase

Imai¹,

Narashima²,

Arai³

et al. 1998

Journal of Biological Chemistry

164

125

View full text Add to dashboard Cite

“…The LOX mechanism (21) includes the enzyme with iron in two redox states (22). The rate-limiting step in the catalyzed reaction is stereoselective abstraction of a hydrogen atom, a proton coupled electron transfer, from a bisallylic methylene of the substrate.…”

mentioning

confidence: 99%

Dynamic Behavior of Fatty Acid Spin Labels within a Binding Site of Soybean Lipoxygenase-1

Gaffney

2006

Biochemistry

View full text Add to dashboard Cite

The putative substrate-binding site in lipoxygenases is long and internal. There is little direct evidence about how the unsaturated fatty acid substrates enter and move within the cavity in order to position correctly for electron transfer reactions with the catalytic non-heme iron. An EPR spectroscopy approach, with spin labeled fatty acids, is taken here to investigate dynamic behavior of fatty acids bound to soybean lipoxygenase-1. The probes are labeled on carbons 5-, 8-, 10-, 12-and 16-of stearic acid. The EPR-determined affinity for the enzyme increases as the length of the alkyl end of the probe increases, with ΔΔG of −190 cal/methylene. The probes in the series exhibit similar enhanced paramagnetic relaxation by the iron center. These results indicate that the members of the series have a common binding site. All of the bound probes undergo considerable local mobility. The stearate spin labeled on carbon 5 has highest affinity for the lipoxygenase and it is a competitive inhibitor, with K i 9 μM. Surprisingly, this stearate labeled near the carboxyl end undergoes more local motion than those labeled in the middle of the chain, when it is bound. This shows that the carboxyl end of the fatty acid spin label is not rigidly docked on the protein. During catalysis, repositioning of the substrate carboxyl on the protein surface may be coupled to motion of portions of the chain undergoing reaction. KeywordsLipoxygenase; spin label; fatty acid; substrate motion; paramagnetic protein Lipoxygenase (LOX) enzymes catalyze the first step in one of the major pathways to molecules derived from arachidonic acid. A theme emerging from the medical perspective on different human lipoxygenases is one of positive and negative influences on human health from these molecules (1,2). Thus, there is much interest in being able to pharmaceutically modulate the activity of selected members of the lipoxygenase family while leaving other members functioning normally (3,4). Indeed, inhibitors selective for 5-, 12-or 15-arachidonic acid lipoxygenases have been developed (5-7). Lipoxygenases from both plant and animal sources have overall structural similarity with a long internal cavity that passes by the catalytic iron ion, based on available X-ray structures (8)(9)(10)(11)(12)(13)(14). Some determinants of substrate binding within this cavity have been examined by mutation and modeling (15)(16)(17)(18)(19)(20), but there is little direct * To whom correspondence should be addressed: Tel. (850) 644-8547. Fax: (850) 644-0481. E-mail: gaffney@bio.fsu.edu. 1 ABBREVIATIONS: cmc, critical micelle concentration; EPR, electron paramagnetic resonance; LOX, any lipoxygenase; SBL1, soybean lipoxygenase isoform-1; 13S-HPODE, 13S-hydroperoxyoctadecadienoic acid; cAOS, coral allene oxide synthase; doxyl-, 1-oxyl-2,2,5,5-tetramethyloxazolidinyl-; x-DSA, a doxyl stearic acid spin label with doxyl ring on carbon x; TEMPOL, 1-oxyl-2,2,6,6-tetramethyl-4-piperidinol; 2A zz , rigid limit separation of outer extrema in spin label EPR spectra; 2A ...

show abstract

Determination of the spin state of iron in native and activated soybean lipoxygenase 1 by paramagnetic susceptibility

Cited by 53 publications

References 22 publications

Identification of a lipoxygenase inhibitor in A431 cells as a phospholipid hydroperoxide glutathione peroxidase

Identification of a lipoxygenase inhibitor in A431 cells as a phospholipid hydroperoxide glutathione peroxidase

Suppression of Leukotriene Formation in RBL-2H3 Cells That Overexpressed Phospholipid Hydroperoxide Glutathione Peroxidase

Dynamic Behavior of Fatty Acid Spin Labels within a Binding Site of Soybean Lipoxygenase-1

Contact Info

Product

Resources

About