11 CIS RETINAL ESTER HYDROLASE IN THE EYE

背景：目前的视觉通路概念涉及到由全反式视黄醇酯通过异构体水解酶形成11-顺式视黄醇。11-顺式视网膜和11-顺式视黄醇酯都是从这个11-顺式视黄醇衍生出来的，这个视觉通路的分支点是已知的。虽然11-顺式视网膜作为视觉发色团的命运已经得到了很好的研究，但确切地说，11-顺式视黄酰基酯是如何被用来为视网膜色素再生提供发色团的还不清楚。初步研究：先前在我们实验室进行的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梯度亚细胞分离表明，11-顺式视黄醇酯和水解酶活性在质膜（PM）上共定位。假设：这些数据支持在RPE PM中存在11-顺式REH酶的假设。这种酶可能控制一种新的、未被探索的视觉通路分支，为视觉色素再生提供视觉染色体。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表征11-cis REH酶。当获得足够数量的该蛋白时，将提高多克隆抗体，并使用免疫荧光法研究该酶在RPE中的定位。生物医学意义：这项研究很重要，因为这一视觉通路分支的细节是完全缺乏的。控制11-顺式视黄酰基酯水解的研究结果可以为理解与视力敏感性降低和/或漂白恢复时间延迟相关的眼部疾病提供理论依据。

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.