| Determination of Recombinant Mannitol-1-phosphate Dehydrogenase Activity from Ectocarpus sp.
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Author:
Date:
2016-11-05
[Abstract] Brown algae belong to a phylogenetic lineage distantly related to green plants and animals, and are found predominantly, but not exclusively, in the intertidal zone, a harsh and frequently changing environment. Because of their unique evolutionary history and of their habitat, brown algae feature several peculiarities in their metabolism. One of these is the mannitol cycle, which plays a central role in their physiology, as mannitol acts as carbon storage, osmoprotectant, and antioxidant. This polyol is derived directly from the photoassimilate fructose-6-phosphate via the action of a ...
[摘要] 褐藻属于与绿色植物和动物遥远相关的系统发生谱系，并且主要发现于但不限于潮间带，一种苛刻且频繁变化的环境。由于它们独特的进化史和它们的栖息地，褐藻具有其代谢中的一些特性。其中之一是甘露醇循环，其在其生理学中发挥中心作用，因为甘露糖醇充当碳储存，渗透保护剂和抗氧化剂。该多元醇通过甘露醇-1-磷酸酯脱氢酶（M1PDH，EC 1.1.1.17）和甘露醇-1-磷酸酶（M1Pase，EC 3.1.3.22）的作用直接从光生酸酯果糖-6-磷酸衍生。该协议描述了在Ectocarpus中鉴定的三种M1PDH之一的重组催化结构域的生物化学表征。该重组催化结构域（下文称为M1PDHcat）使用NAD（H）作为辅因子催化果糖-6-磷酸（F6P）向甘露醇-1-磷酸（M1P）的可逆转化。 M1PDHcat活性在两个方向上测定，即，F6P还原和M1P氧化（图1）。
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图1.甘露醇-1-磷酸脱氢酶的可逆反应
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| Determination of Recombinant Mannitol-1-phosphatase Activity from Ectocarpus sp.
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Author:
Date:
2016-08-20
[Abstract] Brown algae belong to a phylogenetic lineage distantly related to green plants and animals, and are found predominantly, but not exclusively, in the intertidal zone, a harsh and frequently changing environment. Because of their unique evolutionary history and of their habitat, brown algae feature several peculiarities in their metabolism. One of these is the mannitol cycle, which plays a central role in their physiology, as mannitol acts as carbon storage, osmoprotectant, and antioxidant. This polyol is derived directly from the photoassimilate fructose-6-phosphate via the action of a ...
[摘要] 褐藻属于与绿色植物和动物遥远相关的系统发生谱系，并且主要发现于但不限于潮间带，一种苛刻且频繁变化的环境。由于它们独特的进化史和它们的栖息地，褐藻具有其代谢中的一些特性。其中之一是甘露醇循环，其在其生理学中发挥中心作用，因为甘露糖醇充当碳储存，渗透保护剂和抗氧化剂。该多元醇通过甘露醇-1-磷酸酯脱氢酶（M1PDH，EC 1.1.1.17）和甘露醇-1-磷酸酶（M1Pase，EC 3.1.3.22）的作用直接从光生酸酯果糖-6-磷酸衍生。该方案描述了Ectocarpus的重组M1P酶的生物化学表征。 M1P酶催化甘露醇-1-磷酸转化为甘露醇（图1）。
图1.甘露醇-1-磷酸酶催化的反应
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| Determination of Fructokinase Activity from Zobellia galactanivorans
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Author:
Date:
2015-11-05
[Abstract] Mannitol is a polyol that occurs in a wide range of living organisms, where it fulfills different physiological roles. Several pathways have been described for the metabolism of mannitol by bacteria, including the phosphoenolpyruvate-dependent phosphotransferase system (PST) and a M2DH-based catabolic pathway. The latter involves two enzymes, a mannitol-2-dehydrogenase (EC 1.1.1.67) and a fructokinase (EC 2.7.1.4), and has been identified in different bacteria, e.g.,, the marine Bacteroidetes Zobellia galactanivorans (Zg) which had recently gained interest to study ...
[摘要] 甘露醇是在多种活生物体中发生的多元醇，其中它实现不同的生理作用。已经描述了用于由细菌代谢甘露醇的几种途径，包括磷酸烯醇丙酮酸依赖性磷酸转移酶系统（PST）和基于M2DH的分解代谢途径。后者涉及两种酶，甘露醇-2-脱氢酶（EC 1.1.1.67）和果糖激酶（EC 2.7.1.4），并且已经在不同的细菌中鉴定，例如海洋拟杆菌Zobellia galactanivorans （ Zg ），其最近获得了研究大分子多糖降解的兴趣。该方案描述了Zobellia 半乳糖厌氧杆菌的重组果糖激酶（FK）的生物化学表征。 < strong> [原理] 果糖激酶（FK）活性通过以下方法确定：果糖激酶（FK）活性通过使用ATP作为辅因子来催化果糖转化成果糖-6-磷酸。酶偶联测定（图1）。通过FK反应（即果糖磷酸化成果糖-6-磷酸（F6P））形成的ADP由将磷酸烯醇丙酮酸（PEP）转化为丙酮酸的丙酮酸激酶（PK）使用。然后，乳酸脱氢酶（LDH）使用NADH作为辅因子将丙酮酸转化为乳酸。通过跟随在340nm处的吸光度的降低来测量FK活性，其对应于NADH转化为NAD + 。
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