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Hearth Infusion medium

炉底输液介质

Company: Thermo Fisher Scientific
Catalog#: CM1032B
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Campylobacter jejuni γ-glutamyltranspeptidase Activity Assay
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Date:
2016-03-05
[Abstract]  The enzyme γ-glutamyltranspeptidase (GGT, EC 2.3.2.2) is highly conserved among eukaryotic and prokaryotic organisms (Heisterkamp et al., 2008) and has a key function in glutathione metabolism. Although the enzyme is highly conserved and found throughout organisms ranging from bacteria to plants and animals several major difference between eukaryotic and prokaryotic GGT can be noticed. They mainly concern the enzyme localization and posttranslational modification. Eukaryotic GGT is cell membrane anchored and highly glycosylated whereas prokaryotic GGT does not undergo this posttranslational modification and is a soluble periplasmic protein. GGT amino acids sequences of diverse origin exhibit high amino acid similarity (Ong et al., 2008). The prokaryotic GGT enzymes are ... [摘要]  酶γ-谷氨酰转肽酶(GGT,EC 2.3.2.2)在真核和原核生物体中是高度保守的(Heisterkamp等人,2008),并且在谷胱甘肽代谢中具有关键功能。虽然酶是高度保守的,并且在从细菌到植物和动物的整个生物体中发现,可以注意到真核和原核GGT之间的几个主要区别。它们主要涉及酶定位和翻译后修饰。真核GGT是细胞膜锚定和高度糖基化,而原核GGT不经历这种翻译后修饰,并且是可溶性周质蛋白。不同来源的GGT氨基酸序列显示高氨基酸相似性(Ong等人,2008)。原核GGT酶作为酶原产生,装备有典型的原核信号序列,并通过内膜转运到周质中,其中酶经历自催化切割。这种蛋白水解产生成熟的二聚体,其将γ-谷氨酰部分从胞外谷胱甘肽和相关化合物转移到氨基酸或肽(Hanigan等人,1998)。可以容易地测量GGT酶活性,因为其催化γ-谷氨酰基从无色底物L-γ-谷氨酰基-3-羧基-4-硝基苯胺转移至受体甘氨酰甘氨酸,导致产生黄色有色产物,对硝基苯胺(图1),其可以通过分光光度计(图2)测量。在这里我们描述了一种测定革兰氏阴性细菌空肠弯曲杆菌中的GGT活性的方案,其中一些微小的修饰,该方案也适用于其他革兰氏阴性菌/em>细菌种。


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