Q8AXN9 · RPE65_CYNPY

Function

function

Critical isomerohydrolase in the retinoid cycle involved in regeneration of 11-cis-retinal, the chromophore of rod and cone opsins. Catalyzes the cleavage and isomerization of all-trans-retinyl fatty acid esters to 11-cis-retinol which is further oxidized by 11-cis retinol dehydrogenase to 11-cis-retinal for use as visual chromophore. Essential for the production of 11-cis retinal for both rod and cone photoreceptors. Also capable of catalyzing the isomerization of lutein to meso-zeaxanthin an eye-specific carotenoid. The soluble form binds vitamin A (all-trans-retinol), making it available for LRAT processing to all-trans-retinyl ester. The membrane form, palmitoylated by LRAT, binds all-trans-retinyl esters, making them available for IMH (isomerohydrolase) processing to all-cis-retinol. The soluble form is regenerated by transferring its palmitoyl groups onto 11-cis-retinol, a reaction catalyzed by LRAT.

Catalytic activity

Cofactor

Fe2+ (UniProtKB | Rhea| CHEBI:29033 )

Note: Binds 1 Fe2+ ion per subunit.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site180Fe cation (UniProtKB | ChEBI); catalytic
Binding site241Fe cation (UniProtKB | ChEBI); catalytic
Binding site313Fe cation (UniProtKB | ChEBI); catalytic
Binding site527Fe cation (UniProtKB | ChEBI); catalytic

GO annotations

AspectTerm
Cellular Componentendoplasmic reticulum membrane
Cellular Componentmembrane
Cellular Componentplasma membrane
Molecular Functionall-trans-retinyl-ester hydrolase, 11-cis retinol forming activity
Molecular Functionall-trans-retinyl-palmitate hydrolase, 11-cis retinol forming activity
Molecular Functionbeta-carotene 15,15'-dioxygenase activity
Molecular Functioncardiolipin binding
Molecular Functionisomerase activity
Molecular Functionmetal ion binding
Molecular Functionphosphatidylcholine binding
Molecular Functionphosphatidylserine binding
Molecular Functionretinol isomerase activity
Biological Processretinal metabolic process
Biological Processretinoid metabolic process
Biological Processvisual perception
Biological Processzeaxanthin biosynthetic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Retinoid isomerohydrolase
  • EC number
  • Alternative names
    • All-trans-retinyl-palmitate hydrolase
    • Lutein isomerase
    • Meso-zeaxanthin isomerase (EC:5.3.3.22
      ) . EC:5.3.3.22 (UniProtKB | ENZYME | Rhea)
    • Retinal pigment epithelium-specific 65 kDa protein
    • Retinol isomerase

Gene names

    • Name
      RPE65

Organism names

Accessions

  • Primary accession
    Q8AXN9

Subcellular Location

Keywords

PTM/Processing

Features

Showing features for initiator methionine, modified residue, chain, lipidation.

TypeIDPosition(s)Description
Initiator methionine1Removed
Modified residue2N-acetylserine
ChainPRO_00001439482-533Retinoid isomerohydrolase
Lipidation112S-palmitoyl cysteine; in membrane form
Lipidation231S-palmitoyl cysteine; in membrane form
Lipidation329S-palmitoyl cysteine; in membrane form
Lipidation330S-palmitoyl cysteine; in membrane form

Post-translational modification

Palmitoylation by LRAT regulates ligand binding specificity; the palmitoylated form (membrane form) specifically binds all-trans-retinyl-palmitate, while the soluble unpalmitoylated form binds all-trans-retinol (vitamin A).

Keywords

Expression

Tissue specificity

Retinal pigment epithelium specific.

Structure

Family & Domains

Sequence similarities

Belongs to the carotenoid oxygenase family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    533
  • Mass (Da)
    61,264
  • Last updated
    2007-01-23 v3
  • Checksum
    3C9610539122F29D
MSSKVEHPAGGYKKLFETVEELASPITAHVTGRIPVWLTGSLLRCGPGLFEVGSEQFYHLFDGQALLHKFDFKEGHVTYHRRFIRTDTYVRAMTEKRIVITEFGTFAFPDPCKNIFSRFLSYFQGLEVTDNTLVNVYPVGEDYYACTETNYITKVNPETLETIKKVDLCNYVSINGVTAHPLIENDGTVYNIGNCFGKHFSFAYNIVKIPPLQEDKEDPINKAKVVVQFPCSERFKPSYVHSFGLTPNYIVFVEQPVKINLFKFLSSWSIWGANYMDCFESHETMGVWMHVAEKLTGEYLNIKYRTSAFNLFHHINTYEDHGFLIVDLCCWKGFEFIYNYLYLANMRENWEEVKRNAEKAPQPEVRRYVLPLDIHKVDTGKNLVNLPYTTATAILRSDETIWLEPEVLFSGPRLAFEFPQINYKKFGGKDYTFAYGLGLNHFVPDRLSKLNVKTKEIWVWQEPDSYPSEPIFVSQPDAMEEDDGVVLSVIVNPGPGQKPAFLLILNAKDMSEIARAEVDINIPVTFHGMYKKA

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AB095018
EMBL· GenBank· DDBJ
BAC41351.1
EMBL· GenBank· DDBJ
mRNA

Similar Proteins

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