Choo D W, Cheung E, Rando R R
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
FEBS Lett. 1998 Nov 27;440(1-2):195-8. doi: 10.1016/s0014-5793(98)01459-8.
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.
RPE65是一种在脊椎动物视网膜色素上皮（RPE）中发现的主要膜相关蛋白。各种研究表明，这种蛋白质对于视觉功能至关重要，可能在视黄醇处理水平上发挥作用。色素上皮是视觉发色团11-顺式视黄醛产生的解剖部位。异构化途径中的两种关键RPE酶是卵磷脂视黄醇酰基转移酶（LRAT）和异构水解酶，它们将全反式视黄酯加工成11-顺式视黄醇。这两种酶都与膜结合。本文表明，单独使用1 M KCl或添加去污剂CHAPS，RPE65可从RPE膜中大量提取（90-95%）。在使用RPE膜的定量酶分析中，从RPE膜中几乎定量提取RPE65对体外LRAT和异构水解酶活性几乎没有影响，这表明RPE65在体外将全反式视黄醇加工成11-顺式视黄醇的酶促过程中可能没有重要作用。
