6985-27-9Relevant academic research and scientific papers
Synthesis of one double bond-inserted retinal analogs and their binding experiments with opsins: Preparation of novel red-shifted channelrhodopsin variants
Okitsu, Takashi,Yamano, Yumiko,Shen, Yi-Chung,Sasaki, Toshikazu,Kobayashi, Yuka,Morisawa, Shoko,Yamashita, Takahiro,Imamoto, Yasushi,Shichida, Yoshinori,Wada, Akimori
, p. 265 - 272 (2020/11/26)
In optogenetics, red-shifted channelrhodopsins (ChRs) are eagerly sought. We prepared six kinds of new chromophores with one double bond inserted into the polyene side chain of retinal (A1) or 3,4-didehy-droretinal (A2), and examined their binding efficie
Synthesis of apocarotenoids by acyclic cross metathesis and characterization as substrates for human retinaldehyde dehydrogenases
Domínguez, Marta,Pequerul, Raquel,Alvarez, Rosana,Giménez-Dejoz, Joan,Birta, Eszter,Porté, Sergio,Rühl, Ralph,Parés, Xavier,Farrés, Jaume,de Lera, Angel R.
, p. 2567 - 2574 (2018/04/19)
A new synthesis of three apocarotenoids, namely 14′-apo-β-carotenal, 12′-apo-β-carotenal and 10′-apo-β-carotenal, has been achieved that is based on the acyclic cross-metathesis of the hexaene derived from retinal and the corresponding partners. These compounds can be enzymatically converted to their carboxylic acids by the human aldehyde dehydrogenases involved in retinaldehyde oxidation. Their kinetic parameters suggest that these enzymes might play a role in the physiological metabolism of apocarotenoids.
Expansion of first-in-class drug candidates that sequester toxic all-trans-retinal and prevent light-induced retinal degeneration
Zhang, Jianye,Dong, Zhiqian,Mundla, Sreenivasa Reddy,Hu, X. Eric,Seibel, William,Papoian, Ruben,Palczewski, Krzysztof,Golczak, Marcin
, p. 477 - 491 (2015/01/30)
All-trans-retinal, a retinoid metabolite naturally produced upon photoreceptor light activation, is cytotoxic when present at elevated levels in the retina. To lower its toxicity, two experimentally validated methods have been developed involving inhibition of the retinoid cycle and sequestration of excess of all-trans-retinal by drugs containing a primary amine group. We identified the first-in-class drug candidates that transiently sequester this metabolite or slow down its production by inhibiting regeneration of the visual chromophore, 11-cis-retinal. Two enzymes are critical for retinoid recycling in the eye. Lecithin:retinol acyltransferase (LRAT) is the enzyme that traps vitamin A (all-trans-retinol) from the circulation and photoreceptor cells to produce the esterified substrate for retinoid isomerase (RPE65), which converts all-trans-retinyl ester into 11-cis-retinol. Here we investigated retinylamine and its derivatives to assess their inhibitor/substrate specificities for RPE65 and LRAT, mechanisms of action, potency, retention in the eye, and protection against acute light-induced retinal degeneration in mice. We correlated levels of visual cycle inhibition with retinal protective effects and outlined chemical boundaries for LRAT substrates and RPE65 inhibitors to obtain critical insights into therapeutic properties needed for retinal preservation.
The Mycobacterium tuberculosis ORF Rv0654 encodes a carotenoid oxygenase mediating central and excentric cleavage of conventional and aromatic carotenoids
Scherzinger, Daniel,Scheffer, Erdmann,Baer, Cornelia,Ernst, Hansgeorg,Al-Babili, Salim
experimental part, p. 4662 - 4673 (2011/12/04)
Mycobacterium tuberculosis, the causative agent of tuberculosis, is assumed to lack carotenoids, which are widespread pigments fulfilling important functions as radical scavengers and as a source of apocarotenoids. In mammals, the synthesis of apocarotenoids, including retinoic acid, is initiated by the β-carotene cleavage oxygenases I and II catalyzing either a central or an excentric cleavage of β-carotene, respectively. The M. tuberculosis ORF Rv0654 codes for a putative carotenoid oxygenase conserved in other mycobacteria. In the present study, we investigated the corresponding enzyme, here named M. tuberculosis carotenoid cleavage oxygenase (MtCCO). Using heterologously expressed and purified protein, we show that MtCCO converts several carotenoids and apocarotenoids in vitro. Moreover, the identification of the products suggests that, in contrast to other carotenoid oxygenases, MtCCO cleaves the central C15-C15' and an excentric double bond at the C13-C14 position, leading to retinal (C20), β-apo-14'-carotenal (C22) and β-apo-13-carotenone (C18) from β-carotene, as well as the corresponding hydroxylated products from zeaxanthin and lutein. Moreover, the enzyme cleaves also 3,3'-dihydroxy-isorenieratene representing aromatic carotenoids synthesized by other mycobacteria. Quantification of the products from different substrates indicates that the preference for each of the cleavage positions is determined by the hydroxylation and the nature of the ionone ring. The data obtained in the present study reveal MtCCO to be a novel carotenoid oxygenase and indicate that M. tuberculosis may utilize carotenoids from host cells and interfere with their retinoid metabolism. 2010 The Authors Journal compilation
Reactions of beta-carotene with cigarette smoke oxidants. Identification of carotenoid oxidation products and evaluation of the prooxidant/antioxidant effect.
Baker,Krol,Jacobsen,Liebler
, p. 535 - 543 (2007/10/03)
Recent intervention trials reported that smokers given dietary beta-carotene supplementation exhibited an increased risk of lung cancer and overall mortality. beta-Carotene has been hypothesized to promote lung carcinogenesis by acting as a prooxidant in the smoke-exposed lung. We have examined the interactions of cigarette smoke with beta-carotene in model systems. Both whole smoke and gas-phase smoke oxidized beta-carotene in toluene to several products, including carbonyl-containing polyene chain cleavage products and beta-carotene epoxides. A major product of the reaction was identified as 4-nitro-beta-carotene, which was formed by nitrogen oxides in smoke. Both cis and all-trans isomers of 4-nitro-beta-carotene were detected. The hypothesis that smoke-driven beta-carotene autoxidation exerts prooxidant effects was tested in a liposome system. Lipid peroxidation in dilinoleoylphosphatidylcholine liposomes exposed to gas-phase smoke was modestly inhibited by the incorporation of 0.1 mol % beta-carotene. Both the lipid soluble antioxidant alpha-tocopherol and the water soluble antioxidant ascorbate were oxidized more slowly by gas-phase smoke exposure in liposomes containing beta-carotene. These data indicate that beta-carotene exerts weak antioxidant effects against smoke-induced oxidative damage in vitro. It is unlikely that a prooxidant effect of beta-carotene occurs under biologically relevant conditions or is responsible for an increased incidence of lung cancer observed in smokers who consume beta-carotene supplements.
Oxidative degradation of β-carotene and β-apo-8′-carotenal
Mordi, Raphael C.,Walton, John C.,Burton, Graham W.,Hughes, Lise,Ingold U., Keith,Lindsay A., David,Moffatt J., Douglas
, p. 911 - 928 (2007/10/02)
In the self-initiated oxidation of β-carotene with molecular oxygen the rate of oxygen uptake was shown to depend on the oxygen partial pressure. Epoxides, dihydrofurans, carbonyl compounds, carbon dioxide, oligomeric material, traces of alcohols, and probably carboxylic acids were formed. The main products in the early stage of the oxidation were shown to be 5,6-epoxy-β-carotene. 15,15′-epoxy-′-carotene, diepoxides, and a series of β-apo-carotenals and -carotenones. As the oxidation proceeded uncharacterised oligomeric material and the carbonyl compounds became more important and the epoxides degraded. In the final phase of the oxidation the longer chain β-apo-carotenals were themselves oxidized to shorter chain carbonyl compounds, particularly β-apo-13-carotenone, β-ionone, 5,6-epoxy-gb-ionone, dihydroactinidiolide and probably carboxylic acids. The effect of iron, copper and zinc stearates on the product composition and proportions was studied, as was the effect of light. The oxidation was inhibited by 2,6-di-t-butyl-4-methyphenol and α-tocopherol. The oxidations of β-apo-8′-carotenal and retinal under similar conditions were studied briefly, and the main products from the former compound were characterized. The initiation, the formation of the epoxides, the β-apo-carotenals and -carotenones, the successive chain shortening of the aldehydes to the ketones, and the formation of dihydroactinidiolide are explained in terms of free radical peroxidation chemistry.
Exploratory study of β-carotene autoxidation
Mordi,Walton,Burton,Hughes,Ingold,Lindsay
, p. 4203 - 4206 (2007/10/02)
The main products in the early stages of β-carotene autoxidation were epoxides, β-ionone, β-apo-13-carotenone, retinal, and related carbonyl compounds; in the final mixture short chain carbonyl compounds predominated.
Dependence of the Triplet Potential of Retinal Homologues on the Chain Length: Resonance Raman Spectroscopy and Analysis of Triplet-Sensitized Isomerization
Mukai, Yumiko,Hashimoto, Hideki,Koyama, Yasushi
, p. 4042 - 4051 (2007/10/02)
The Raman spectra of triplet species produced from the all-trans, 7-cis and 9-cis isomers of β-ionylideneacetaldehyde (C15 aldehyde) and of β-ionylidenecrotonaldehyde (C17 aldehyde) were recorded.Each isomer of C15 aldehyde showed its own triplet Raman spectrum, while all the isomers of C17 aldehyde showed an identical triplet spectrum.The results were compared with those of isomeric retinal (C20 aldehyde) and retinylideneacetaldehyde (C22 aldehyde) obtained previously.Triplet-sensitized isomerization as well as direct photoisomerization of the all-trans isomer and the complete set of mono-cis isomers of C15, C17, C20, and C22 aldehydes were analyzed by HPLC.Mutual isomerization among the all-trans was seen for C17, C20, and C22 aldehydes.The quantum yield of triplet-sensitized isomerization for each isomer of the above aldehydes was determined. all the results are discussed in terms of triplet potentials with minima at cis and trans positions, the relative stability being dependent on the length of the polyene chain; the cis minima are as stable as the trans minimum for C15 aldehyde, while the cis minima are far less stable than the trans minimum for C17, C20, and C22 aldehydes.
