2008年10月
Highly efficient retinal metabolism in cones
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
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- 巻
- 105
- 号
- 41
- 開始ページ
- 16051
- 終了ページ
- 16056
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1073/pnas.0806593105
- 出版者・発行元
- NATL ACAD SCIENCES
After bleaching of visual pigment in vertebrate photoreceptors, all-trans retinal is reduced to all-trans retinol by retinol dehydrogenases (RDHs). We investigated this reaction in purified carp rods and cones, and we found that the reducing activity toward all-trans retinal in the outer segment (OS) of cones is > 30 times higher than that of rods. The high activity of RDHs was attributed to high content of RDH8 in cones. In the inner segment (IS) in both rods and cones, RDH8L2 and RDH13 were found to be the major enzymes among RDH family proteins. We further found a previously undescribed and effective pathway to convert 11-cis retinol to 11-cis retinal in cones: this oxidative conversion did not require NADP(+) and instead was coupled with reduction of all-trans retinal to all-trans retinol. The activity was > 50 times effective than the oxidizing activity of RDHs that require NADP(+). These highly effective reactions of removal of all-trans retinal by RDH8 and production of 11-cis retinal by the coupling reaction are probably the underlying mechanisms that ensure effective visual pigment regeneration in cones that function under much brighter light conditions than rods.
- リンク情報
- ID情報
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- DOI : 10.1073/pnas.0806593105
- ISSN : 0027-8424
- PubMed ID : 18836074
- Web of Science ID : WOS:000260240900073