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Lack of effect of RPE65 removal on the enzymatic processing of all‐ trans ‐retinol into 11‐ cis ‐retinol in vitro
Author(s) -
Choo Dong Won,
Cheung Eric,
Rando Robert R
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01459-8
Subject(s) - rpe65 , retinol , visual phototransduction , biochemistry , enzyme , retinal , retinal pigment epithelium , chemistry , membrane , in vitro , retinaldehyde , cis trans isomerases , biology , vitamin , isomerase , peptidylprolyl isomerase
RPE65 is a major membrane associated protein found in the vertebrate retinal pigment epithelium (RPE). Various studies have shown this protein to be essential for visual function, possibly at the level of the processing of retinoids. The pigment epithelium is the anatomical site in which the visual chromophore 11‐ cis retinal is generated. The two critical RPE enzymes in the isomerization pathway are lecithin retinol acyl transferase (LRAT) and isomerohydrolase, which processes all‐ trans ‐retinyl esters into 11‐ cis ‐retinol. Both enzymes are membrane bound. It is shown here that RPE65 can be largely extracted (90–95%) from RPE membranes by 1 M KCl by itself, or with added detergent CHAPS. The almost quantitative extraction of RPE65 from RPE membranes has little or no effect on in vitro LRAT and isomerohydrolase activities in quantitative enzymatic assays using RPE membranes, suggesting that RPE65 may not have an important role to play in the enzymatic processing of all‐ trans ‐retinol into 11‐ cis ‐retinol in vitro.