Lot6p from Saccharomyces cerevisiae is a FMN-dependent reductase with a potential role in quinone detoxification.
Lot6p from Saccharomyces cerevisiae is a FMN-dependent reductase with a potential role in quinone detoxification.
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来自酿酒酵母的 Lot6p 是一种 FMN 依赖性还原酶，在醌解毒中具有潜在作用。
DOI：
10.1111/j.1742-4658.2007.05682.x
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Macheroux,Peter
中科院分区：
文献类型：
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作者：
Sollner,Sonja;Nebauer,Ruth;Ehammer,Heidemarie;Prem,Anna;Deller,Sigrid;Palfey,BruceA;Daum,Günther;Macheroux,Peter
NAD（P）H：醌受体氧化还原酶是在许多组织的细胞质中表达的黄素酶，并通过催化严格的双电子还原来保护亲电子醌的细胞毒性作用。已经报道了来自几种哺乳动物来源（例如人、小鼠和大鼠）和来自植物物种的此类酶。在这里，我们报告的Lot 6p（YLR 011 wp），第一个可溶性醌还原酶从单细胞模式生物酿酒酵母的鉴定。使用针对Lot 6p的抗体进行的定位研究以及Lot 6p-GFP的显微镜检查证明了酶在酵母细胞胞质溶胶中的蓄积。尽管与1型人醌还原酶只有23%的相似性，但Lot 6p具有与其人类对应物相似的生物化学性质。该酶催化一系列天然和人工醌底物的双电子还原，以NADH或NADPH为代价。动力学机制遵循乒乓双-双反应方案，各种醌的Km值为1.6-11 µ m。 醌还原酶家族的两种著名抑制剂双香豆素和汽巴龙Marine可与Lot 6p结合并抑制其活性。体内实验表明，Lot 6p的酶活性与Δ lot 6和Lot 6p过表达菌株的表型一致，表明Lot 6p可能在酵母中管理氧化应激中发挥作用。
NAD(P)H:quinone acceptor oxidoreductases are flavoenzymes expressed in the cytoplasm of many tissues and afford protection against the cytotoxic effects of electrophilic quinones by catalyzing a strict two‐electron reduction. Such enzymes have been reported from several mammalian sources, e.g. human, mouse and rat, and from plant species. Here, we report identification of Lot6p (YLR011wp), the first soluble quinone reductase from the unicellular model organismSaccharomyces cerevisiae. Localization studies using an antibody raised against Lot6p as well as microscopic inspection of Lot6p‐GFP demonstrated accumulation of the enzyme in the cytosol of yeast cells. Despite sharing only 23% similarity to type 1 human quinone reductase, Lot6p possesses biochemical properties that are similar to its human counterpart. The enzyme catalyzes a two‐electron reduction of a series of natural and artificial quinone substrates at the expense of either NADH or NADPH. The kinetic mechanism follows a ping‐pong bi–bi reaction scheme, withKMvalues of 1.6–11 µmfor various quinones. Dicoumarol and Cibacron Marine, two well‐known inhibitors of the quinone reductase family, bind to Lot6p and inhibit its activity.In vivoexperiments demonstrate that the enzymatic activity of Lot6p is consistent with the phenotype of bothΔlot6and Lot6p overexpressing strains, suggesting that Lot6p may play a role in managing oxidative stress in yeast.