ALOX15B - Arachidonate 15-lipoxygenase B - human protein (Function)
 
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ALOX15B »  Arachidonate 15-lipoxygenase B
 
Gene name:  ALOX15B
Family name: Lipoxygenase
Entry whose protein(s) existence is based on evidence at protein level
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GENE REF ISO

Function

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Overview 
Non-heme iron-containing dioxygenase that catalyzes the stereo-specific peroxidation of free and esterified polyunsaturated fatty acids generating a spectrum of bioactive lipid mediators. Converts arachidonic acid to 15S-hydroperoxyeicosatetraenoic acid/(15S)-HPETE. Also acts on linoleic acid to produce 13-hydroxyoctadecadienoic acid/13-HPODE. Has no detectable 8S-lipoxygenase activity but reacts with (8S)-HPETE to produce (8S,15S)-diHPETE. May regulate progression through the cell cycle and cell proliferation. May also regulate cytokine secretion by macrophages and therefore play a role in the immune response. May also regulate macrophage differentiation into proatherogenic foam cells.  
7
  • CuratedUniProtKB
GO molecular function 
Arachidonate 15-lipoxygenase activitydefinition[GO:0050473]  
4
  • IDAUniProtKB
Arachidonate 8(S)-lipoxygenase activitydefinition[GO:0036403] silver  
  • IEAOrtholog Compara
Calcium ion bindingdefinition[GO:0005509]  
1
  • IDAUniProtKB
Iron ion bindingdefinition[GO:0005506]  
1
  • IDAUniProtKB
Linoleate 13S-lipoxygenase activitydefinition[GO:0016165]  
1
  • IDAUniProtKB
Lipid bindingdefinition[GO:0008289]  
  • IEAUniProtKB KW
GO biological process 
Apoptotic processdefinition[GO:0006915]  
1
  • TASUniProtKB
Arachidonic acid metabolic processdefinition[GO:0019369]  
4
  • IDAUniProtKB
Hepoxilin biosynthetic processdefinition[GO:0051122]  
  • ISSOrtholog Curator
Linoleic acid metabolic processdefinition[GO:0043651] silver  
  • IEAOrtholog Compara
Lipid metabolic processdefinition[GO:0006629]  
1
  • TASUniProtKB
Negative regulation of cell cycledefinition[GO:0045786]  
1
  • IDAUniProtKB
Negative regulation of cell migrationdefinition[GO:0030336]  
1
  • TASUniProtKB
Negative regulation of cell proliferationdefinition[GO:0008285]  
2
  • IMPUniProtKB
Negative regulation of growthdefinition[GO:0045926]  
1
  • IDAUniProtKB
Oxidation-reduction processdefinition[GO:0055114]  
  • IEAUniProtKB KW
Positive regulation of chemokine secretiondefinition[GO:0090197]  
1
  • IMPUniProtKB
Positive regulation of keratinocyte differentiationdefinition[GO:0045618] silver  
  • IEAOrtholog Compara
Positive regulation of macrophage derived foam cell differentiationdefinition[GO:0010744]  
1
  • IMPUniProtKB
Positive regulation of peroxisome proliferator activated receptor signaling pathwaydefinition[GO:0035360] silver  
  • IEAOrtholog Compara
Prostate gland developmentdefinition[GO:0030850]  
1
  • NASUniProtKB
Regulation of epithelial cell differentiationdefinition[GO:0030856]  
1
  • NASUniProtKB
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reactions
EC 1.13.11.33: Arachidonate + O(2) (5Z,8Z,11Z,13E)-(15S)-15-hydroperoxyicosa-5,8,11,13-tetraenoate.  
4
  • CuratedUniProtKB
EC 1.13.11.-: Linoleate + O(2) (9Z,11E)-13-hydroxyoctadeca-9,11-dienoate.  
4
  • CuratedUniProtKB
It requires the following cofactor
Binds 1 iron ion per subunit.  
1
  • CuratedUniProtKB
Pathways 
This protein is involved in the following pathway
According to KEGG, this protein belongs to the following pathways:
Arachidonic acid metabolism  hsa00590+247  
Metabolic pathways  hsa01100+247  
According to Reactome, this protein belongs to the following pathway:
Synthesis of 15-eicosatetraenoic acid derivatives  REACT_150422  
Caution 
Despite its homology with mouse Alox8 (AC O35936), it seems not to have any 8S-lipoxygenase activity on arachidonate.  
  • CuratedUniProtKB
 

Biophysicochemical properties

Kinetic parameters
KM 25 uM for arachidonate (isoform A at pH 7.4 and 20 degrees Celsius)
KM 10 uM for linoleate (isoform A at pH 7.4 and 20 degrees Celsius)
KM 1100 uM for arachidonate (isoform D at pH 7.4 and 20 degrees Celsius)
Vmax 4 umol/min/mg enzyme with arachidonate as substrate (isoform A at pH 7.4 and 20 degrees Celsius)
Vmax 2 umol/min/mg enzyme with arachidonate as substrate (isoform D at pH 7.4 and 20 degrees Celsius)
Vmax 4 umol/min/mg enzyme with linoleate as substrate (isoform A at pH 7.4 and 20 degrees Celsius)

Keywords

Biological process 
Lipid metabolism  definition   [KW-0443]
Molecular function 
Dioxygenase  definition   [KW-0223]
Oxidoreductase  definition   [KW-0560]
Technical term 
Reference proteome  definition   [KW-1185]
 

Further external links

GeneWiki: ALOX15B
GenomeRNAi: 247
PRO: PR:O15296