Dimerisation of N-acetyl-L-tyrosine ethyl ester and Aβ peptides via formation of dityrosine
Dimerisation of N-acetyl-L-tyrosine ethyl ester and Aβ peptides via formation of dityrosine
复制标题
DOI：
10.1080/10715760500329721
复制
发表时间：
2006-01-01
影响因子：
3.3
通讯作者：
Barrow, CJ
中科院分区：
文献类型：
--
作者：
Ali, FE;Leung, A;Barrow, CJ
阿尔茨海默病(AD)的特征是形成淀粉样沉积，主要由淀粉样β-肽(Aβ)组成。这种多肽已被证明与铜和铁等氧化还原活性金属离子结合，导致活性氧物种(ROS)的产生和过氧化氢(H_2O_2)的形成。过氧化氢的产生与阿尔茨海默病的Aβ神经毒性和神经变性有关。由于酪氨酸基的相对稳定性，酪氨酸残基(Tyr-10)被认为是Aβ神经毒性的关键。这种残基也被证明对Aβ聚集和淀粉样蛋白的形成很重要。Aβ酪氨酸基的形成可能导致聚集性的增加，这是一个早期的聚集步骤，这一点得到了淀粉样斑块中Dityroine的鉴定的支持。二核苷酸的形成在Aβ聚集和神经毒性中的作用尚不确定，部分原因是目前还没有简便的方法来合成含有二核苷酸的Aβ二聚体。本文报道了用辣根过氧化物酶和H_2O_2催化N-乙酰基-L酪氨酸乙酯的二聚化反应，并将优化的合成条件应用于完全无保护的Aβ多肽。我们还报告了一种简单的荧光平板阅读器方法，用于监测Aβ二聚体的形成。
Alzheimer's disease (AD) is characterised by the formation of amyloid deposits composed primarily of the amyloid beta-peptide (A beta). This peptide has been shown to bind redox active metals ions such as copper and iron, leading to the production of reactive oxygen species (ROS) and formation of hydrogen peroxide (H2O2). The generation of H2O2 has been linked with A beta neurotoxicity and neurodegeneration in AD. Because of the relative stability of a tyrosyl radical, the tyrosine residue (Tyr-10) is believed to be critical to the neurotoxicity of A beta. This residue has also been shown to be important to A beta aggregation and amyloid formation. It is possible that the formation of an A beta tyrosyl radical leads to increased aggregation via the formation of dityrosine as an early aggregation step, which is supported by the identification of dityrosine in amyloid plaque. The role of dityrosine formation in A beta aggregation and neurotoxicity is as yet undetermined, partly because there are no facile methods for the synthesis of A beta dimers containing dityrosine. Here we report the use of horseradish peroxidase and H2O2 to dimerise N-acetyl-L-tyrosine ethyl ester and apply the optimised conditions for dityrosine formation to fully unprotected A beta peptides. We also report a simple fluorescent plate reader method for monitoring A beta dimerisation via dityrosine formation.