IUBMB Enzyme Nomenclature


Accepted name: retinoid isomerohydrolase

Reaction: an all-trans-retinyl ester + H2O = 11-cis-retinol + a fatty acid

For diagram of reaction click here.

Other name(s): all-trans-retinyl-palmitate hydrolase (ambiguous); retinol isomerase (ambiguous); all-trans-retinol isomerase:hydrolase (ambiguous); all-trans-retinylester 11-cis isomerohydrolase; RPE65 (gene name)

Systematic name: all-trans-retinyl ester acylhydrolase, 11-cis retinol forming

Comments: This enzyme, which operates in the retinal pigment epithelium (RPE), catalyses the cleavage and isomerization of all-trans-retinyl fatty acid esters to 11-cis-retinol, a key step in the regeneration of the visual chromophore in the vertebrate visual cycle [4]. Interaction of the enzyme with the membrane is critical for its enzymatic activity [6].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 106389-24-6


1. Blaner, W.S., Das, S.R., Gouras, P. and Flood, M.T. Hydrolysis of 11-cis- and all-trans-retinyl palmitate by homogenates of human retinal epithelial cells. J. Biol. Chem. 262 (1987) 53-58. [PMID: 3793734]

2. Bernstein, P.S., Law, W.C. and Rando, R.R. Isomerization of all-trans-retinoids to 11-cis-retinoids in vitro. Proc. Natl. Acad. Sci. USA 84 (1987) 1849-1853. [PMID: 3494246]

3. Bridges, C.D. and Alvarez, R.A. The visual cycle operates via an isomerase acting on all-trans retinol in the pigment epithelium. Science 236 (1987) 1678-1680. [PMID: 3603006]

4. Moiseyev, G., Chen, Y., Takahashi, Y., Wu, B.X. and Ma, J.X. RPE65 is the isomerohydrolase in the retinoid visual cycle. Proc. Natl. Acad. Sci. USA 102 (2005) 12413-12418. [PMID: 16116091]

5. Nikolaeva, O., Takahashi, Y., Moiseyev, G. and Ma, J.X. Purified RPE65 shows isomerohydrolase activity after reassociation with a phospholipid membrane. FEBS J. 276 (2009) 3020-3030. [PMID: 19490105]

6. Golczak, M., Kiser, P.D., Lodowski, D.T., Maeda, A. and Palczewski, K. Importance of membrane structural integrity for RPE65 retinoid isomerization activity. J. Biol. Chem. 285 (2010) 9667-9682. [PMID: 20100834]

[EC created 1989 (EC created 1989, incorporated 2011), modified 2011]

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