11 CIS RETINAL ESTER HYDROLASE IN THE EYE

背景：目前视觉通路的概念涉及通过异构水解酶从全反式视黄酯形成11-顺式视黄醇。11-顺式视黄酸酯和11-顺式视黄基酯均衍生自该11-顺式视黄醇，并且视觉通路的该分支点是已知的。尽管11-顺式视黄酸作为视觉发色团的命运已经被很好地研究，但是11-顺式视黄酯如何被用于提供视网膜发色团用于色素再生的确切情况还不清楚。初步研究：在我们实验室进行的先前研究确定了牛视网膜色素上皮（RPE）微粒体中存在11-顺式视黄酯水解酶（REH）活性。蔗糖和Percol梯度的亚细胞分离表明，11-顺式视黄酯和水解酶活性共定位于质膜（PM）。假设：这些数据支持在RPE PM中存在11-顺式REH酶的假设。这种酶可能控制一个新的，未开发的分支的视觉途径，提供视觉染色体的视色素再生。方法：我们建议扩展我们目前的研究，包括完整的纯化和生化特性的11-顺式REH酶。当获得足够量的该蛋白时，将产生多克隆抗体，并将使用免疫荧光方法来研究该酶在RPE中的定位。生物医学相关性：这项研究很重要，因为视觉通路的这个分支的细节完全缺乏。控制11-顺式视黄酯水解的研究结果可以为理解与视觉敏感性降低和/或漂白恢复时间延迟相关的眼部疾病提供依据。

Background: Current concept of the visual pathway involves the formation of 11-cis retinol from all-trans retinyl esters by an isomerohydrolase. Both 11-cis retinal and 11-cis retinyl esters are derived from this 11-cis retinol and this branch point of the visual pathway is known. Although the fate of 11-cis retinal to serve as visual chromophore has been well studied, exactly how 11-cis retinyl esters are used to supply retinal chromophores for pigment regeneration is not known. Preliminary Studies: Previous studies conducted in our laboratory established the presence of an 11-cis retinyl ester hydrolase (REH) activity in the bovine retinal pigment epithelium (RPE) microsomes. Subcellular fractionation by sucrose and Percol gradients showed that 11- cis retinyl esters and hydrolase enzyme activity are co-localized at the plasma membrane (PM). Hypothesis: These data support the hypothesis that in the RPE PM, there is an 11-cis REH enzyme. This enzyme may control a novel, unexplored branch of the visual pathway to supply visual chromosomes for visual pigment regeneration. Methods: We propose to extend our current research to include complete purification and biochemical characterization of this 11-cis REH enzyme. When a sufficient amount of this protein is available, polyclonal antibody will be raised and immunofluorescence method will be used to study the localization of this enzyme in the RPE. Biomedical Relevance: This research is important because details of this branch of the visual pathway is completely lacking. Results from studies on the control of 11-cis retinyl ester hydrolysis could provide rationale for understanding those ocular diseases associated with a reduction of visual sensitivity and/or delays in the time course of bleaching recovery.