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Information about Lipoxygenase

Rabbit 15-lipoxygenase (blue) with inhibitor (yellow) bound in the active site
Rabbit 15-lipoxygenase
Identifiers
SymbolALOX15
Entrez246
HUGO433
PDB1LOX
Other data
EC number1.13.11.33


Lipoxygenases are iron-containing enzymes that catalyse the dioxygenation of polyunsaturated fatty acids in reaction:

fatty acid + O2 = fatty acid hydroperoxide


Lipoxygenases are found in plants, animals and fungi. Products of lipoxygenases are involved in diverse cell functions.

Biochemical classification

EC 1.13.11.12lipoxygenase(linoleate:oxygen 13-oxidoreductase)linoleate + O2 = (9Z,11E,13S)-13-hydroperoxyoctadeca-9,11-dienoate
EC 1.13.11.31arachidonate 12-lipoxygenase(arachidonate:oxygen 12-oxidoreductase)arachidonate + O2 = (5Z,8Z,10E,12S,14Z)-12-hydroperoxyicosa-5,8,10,14-tetraenoate
EC 1.13.11.33arachidonate 15-lipoxygenase(arachidonate:oxygen 15-oxidoreductase)arachidonate + O2 = (5Z,8Z,11Z,13E,15S)-15-hydroperoxyicosa-5,8,11,13-tetraenoate
EC 1.13.11.34arachidonate 5-lipoxygenase(arachidonate:oxygen 5-oxidoreductase)arachidonate + O2 = leukotriene A4 + H2
EC 1.13.11.40arachidonate 8-lipoxygenase(arachidonate:oxygen 8-oxidoreductase)arachidonate + O2 = (5Z,8R,9E,11Z,14Z)-8-hydroperoxyicosa-5,9,11,14-tetraenoate


Soybean Lipoxygenase 1 exhibits the largest H/D kinetic isotope effect (KIE) on kcat (kH/kD) (81 near room temperature) so far reported for a biological system.

Structure

The crystal structures of soybean and rabbit lipoxygenases are known. The protein consists of a small N-terminal domain and a major C-terminal domain, which contains the active site. In both plant and mammalian enzymes, the N-terminal domain contains an eight-stranded antiparallel β-barrel, but in the soybean lipoxygenases this domain is significantly larger than in the rabbit enzyme. It has been noted that the β-barrel domain of mammalian lipoxygenase is more similar in sequence, size and structure to an analogous C-terminal β-barrel domain in the mammalian lipases than to the homologous domain in plant lipoxygenases. The plant lipoxygenases can be enzymatically cleaved into two fragments which stay tightly associated while the enzyme remains active; separation of the two domains leads to loss of catalytic activity. The C-terminal (catalytic) domain consists of 18-22 helices and one (in rabbit enzyme) or two (in soybean enzymes) antiparallel β-sheets at the opposite end from the N-terminal β-barrel. The two long central helices cross at the active site; both helices include internal stretches of π-helix that provide three histidine (His) ligands to the active site iron. Two cavities in the major domain of soybean lipoxygenase-1 (cavities I and II) extend from the surface to the active site. The funnel-shaped cavity I may function as a dioxygen channel; the long narrow cavity II is presumably a substrate pocket. The more compact mammalian enzyme contains only one boot-shaped cavity (cavity II). In soybean lipoxygenase-3 there is a third cavity which runs from the iron site to the interface of the β-barrel and catalytic domains. Cavity III, the iron site and cavity II form a continuous passage throughout the protein molecule.

The active site iron is coordinated by Nε of three conserved His residues and one oxygen of the C-terminal carboxyl group. In addition, in soybean enzymes the side chain oxygen of asparagine is weakly associated with the iron. In rabbit lipoxygenase, this Asn residue is replaced with His which coordinates the iron via Nδ atom. Thus, the coordination number of iron is either five or six, with a hydroxyl or water ligand to a hexacoordinate iron.

References

  1. Tejero, I.; Eriksson, L. A.; Gonzalez-Lafont, A.; Marquet, J.; Lluch, J. M. Hydrogen Abstraction by Soybean Lipoxygenase-1. Density Functional Theory Study on Active Site Models in Terms of Gibbs Free Energies http://dx.doi.org/10.1021/jp040114nJ. Phys. Chem. B, 2004,108, 13831
  • Kulkarni, A.P. (2001). "Lipoxygenase - a versatile biocatalyst for biotransformation of endobiotics and xenobiotics". Cell Mol Life Sci 58: 1805–1825. PMID 11766881. .
  • Nelson, M.J. and Seitz, S.P. (1994). "The structure and function of lipoxygenase". Curr Opin Struct Biol 4: 878–884. PMID 8161558. .

External links

 •  • [ e]
Oxidoreductases: monooxygenases (EC 1.13)
1.13.11 - two atoms of oxygenCatechol dioxygenase - Homogentisate 1,2-dioxygenase - Cysteine dioxygenase - 4-Hydroxyphenylpyruvate dioxygenase - Indoleamine 2,3-dioxygenase - Lipoxygenase (5)
1.13.12 - one atom of oxygenFirefly luciferase
1.13.99 - otherInositol oxygenase
 •  • [ e]
Carrier proteins, metalloproteins: iron-binding proteins
hemeFerritin (Bacterioferritin) - Lactoferrin - Transferrin
nonhemeHemerythrin - Inositol oxygenase - Iron-sulfur protein - Lipoxygenase - Tyrosine hydroxylase
The Entrez Global Query Cross-Database Search System is a powerful federated search engine, or web portal that allows users to search many discrete health sciences databases at the National Center for Biotechnology Information (NCBI) website.
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Hugo is a male given name, a latinized form of the name Hugh, a German/Teutonic name meaning "Bright in Mind and Spirit".

Hugo is one of the most popular names in Europe ranking as high as #2 in France, #6 in Spain, and #7 in Belgium in 2006.
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Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. This data, typically obtained by X-ray crystallography or NMR spectroscopy, is submitted by biologists and biochemists from around the world, is released into the public domain,
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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3, 4, 6
(amphoteric oxide)
Electronegativity 1.83 (Pauling scale)
Ionization energies
(more) 1st: 762.5 kJmol−1
2nd: 1561.9 kJmol−1
3rd: 2957 kJmol−1

Atomic radius 140 pm
Atomic radius (calc.
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Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions.[1] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products.
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Dioxygenases (a type of oxygenase incorporating two atoms of oxygen) can refer to:
  • Catechol dioxygenase
  • Cysteine dioxygenase
  • 4-hydroxyphenylpyruvate dioxygenase
  • Lipoxygenase

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Types of Fats in Food
  • Unsaturated fat
  • Monounsaturated fat
  • Polyunsaturated fat
  • Trans fat
  • Omega: 3, 6, 9

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Types of Fats in Food
  • Unsaturated fat
  • Monounsaturated fat
  • Polyunsaturated fat
  • Trans fat
  • Omega: 3, 6, 9

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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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Arachidonate 5-lipoxygenase (5-lipoxygenase, 5-LO or Alox5), which transforms EFAs into leukotrienes, is a current target for pharmaceutical intervention in a number of diseases.
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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The kinetic isotope effect (KIE) is a variation in the reaction rate of a chemical reaction when an atom in one of the reactants is replaced by one of its isotopes. It is also called isotope fractionation, although this term is technically somewhat broader in meaning.
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The active site of an enzyme contains the catalytic and binding sites. The structure and chemical properties of the active site allow the recognition and binding of the substrate.
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Histidine (abbreviated as His or H)[1] is one of the 20 most common natural amino acids present in proteins. In the nutritional sense, in humans, histidine is considered an essential amino acid, but mostly only in children.
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side chain in organic chemistry and biochemistry is a part of a molecule that is attached to a core structure. An R group is a generic label for a side chain which can be anything; however, it is typically stable and covalently linked to the adjoining atom.
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For other articles using the abbreviation or acronym asn see ASN.


Asparagine (abbreviated as Asn or N; Asx or B
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Density functional theory (DFT) is a quantum mechanical theory used in physics and chemistry to investigate the ground state of many-body systems, in particular atoms, molecules and the condensed phases.
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The active site of an enzyme contains the catalytic and binding sites. The structure and chemical properties of the active site allow the recognition and binding of the substrate.
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Gibbs may refer to:

People

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Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. This data, typically obtained by X-ray crystallography or NMR spectroscopy, is submitted by biologists and biochemists from around the world, is released into the public domain,
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Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. This data, typically obtained by X-ray crystallography or NMR spectroscopy, is submitted by biologists and biochemists from around the world, is released into the public domain,
..... Click the link for more information.
Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. This data, typically obtained by X-ray crystallography or NMR spectroscopy, is submitted by biologists and biochemists from around the world, is released into the public domain,
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Orientations of Proteins in Membranes (OPM) database provides spatial positions of protein three-dimensional structures with respect to the lipid bilayer. [1] [2]. [2].
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule (the reductant, also called the hydrogen acceptor or electron donor) to another (the oxidant, also called the hydrogen donor or electron acceptor).
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An oxygenase is any enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air) to it. The oxygenases form a class of oxidoreductases; their EC number is EC 1.13 or EC 1.14.
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