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首页> 外文期刊>Infection and immunity >gamma-Glutamyltransferase from the outer cell envelope of Treponema denticola ATCC 35405.
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gamma-Glutamyltransferase from the outer cell envelope of Treponema denticola ATCC 35405.

机译：密螺旋体ATCC 35405的细胞外被膜中的γ-谷氨酰转移酶。

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摘要

The human oral spirochete Treponema denticola ATCC 35405 was shown to exhibit relatively high enzyme activity toward the gamma-glutamyl amide bond present in N-gamma-L-glutamyl-4-nitroaniline. The enzyme responsible for this catalysis (gamma-glutamyltransferase [GGT]; EC 2.3.2.2) was purified by means of fast protein liquid chromatography to two sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-pure forms from a mild (0.1%) Triton X-100 extract of washed cells. The GGT was studied primarily with regard to its hydrolytic activity by using N-gamma-L-glutamyl-4-nitroaniline as a substrate, although the GGT was shown to catalyze transpeptidation reactions. The high-molecular-mass form of the GGT gave a value of about 213 kDa by SDS-PAGE when heat treatment was omitted and one of 26 kDa after heat treatment; mass spectrometry gave a value of 26.877. The larger form may represent an aggregate with nonprotein structures (possibly of a carbohydrate nature). The preliminary N-terminal sequence of the GGT is MKKPLIGITGSXLYETSQXXF. The enzyme was highly active on glutathione, transferring its Glu residue either to a water molecule or to the Gly-L-Leu dipeptide. The GGT stability was absolutely dependent on the presence of free thiol(s), while no evidence of metalloenzyme nature was obtained. The proposed location of the GGT in the outer cell envelope and its high activity on glutathione, a major nonprotein thiol present in virtually all cells, suggest that the GGT may play a role in the propagation of T. denticola within inflamed periodontal tissues.
机译：人类口腔螺旋藻密螺旋体ATCC 35405被证明对存在于N-γ-L-谷氨酰基-4-硝基苯胺中的γ-谷氨酰胺键具有较高的酶活性。通过快速蛋白质液相色谱将负责该催化作用的酶（γ-谷氨酰转移酶[GGT]; EC 2.3.2.2）纯化，从轻度（0.1）纯化为两种十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）-纯形式。 ％）洗涤细胞的Triton X-100提取物。尽管GGT显示出催化转肽反应的作用，但主要通过使用N-γ-L-谷氨酰-4-硝基苯胺作为底物来研究GGT的水解活性。当省略热处理时，通过SDS-PAGE，GGT的高分子形式的值约为213 kDa，而在热处理后为26 kDa之一。质谱的值为26.877。较大的形式可能表示具有非蛋白质结构（可能具有碳水化合物性质）的聚集体。 GGT的初步N端序列是MKKPLIGITGSXLYETSQXXF。该酶对谷胱甘肽具有高活性，可将其Glu残基转移到水分子或Gly-L-Leu二肽上。 GGT的稳定性绝对取决于游离硫醇的存在，而没有获得金属酶性质的证据。拟议中的GGT在外层细胞膜中的位置及其对谷胱甘肽（几乎所有细胞中都存在的主要非蛋白质硫醇）的高活性表明，GGT可能在发炎的牙周组织内的T. denticola繁殖中发挥作用。

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