Department of Chemistry, National Sun Yat-sen University, Taiwan, and National Sun Yat-sen University-Kaohsiung Medical University Joint Research Center, Kaohsiung, Taiwan.
Anal Chem. 2010 Nov 1;82(21):8775-9. doi: 10.1021/ac102020n. Epub 2010 Oct 14.
This study reports a simple colorimetric method for the sensitive detection of S-adenosylhomocysteine hydrolase (SAHH) activity and inhibition using fluorosurfactant-capped gold nanoparticles (FSN-AuNPs). FSN stabilizes the AuNPs against conditions of high ionic strength, and FSN-AuNPs are merely aggregated in the presence of homocysteine (HCys) and cysteine. Because of this feature, FSN-AuNPs were found to be dispersed in the presence of S-adenosylhomocysteine (SAH) that lacks a free thiol group. After SAHH catalyzed the hydrolysis of SAH, the produced HCys molecules were bound to the surface of AuNPs through the formation of Au-S bonds. As a result, the nanoparticle (NP) aggregation occurred through electrostatic attraction between each HCys-attached AuNP. This approach had a minimum detectable concentration of 100 units/L (~6 nM). Additionally, because adenosine analogs are capable of inhibiting SAHH activity, the addition of adenosine analogs to a solution containing SAH and SAHH resulted in the suppression of hydrolyzed SAH-induced NP aggregation. Adenosine analogs exhibited the following trend in the half-maximal inhibitory concentrations: adenosine > adenosine monophosphate > adenosine diphosphate ~ adenosine triphosphate. We have demonstrated that the combination of SAHH inhibition and FSN-AuNPs can be utilized for the selective detection of adenosine.
本研究报告了一种使用氟表面活性剂包覆的金纳米粒子（FSN-AuNPs）灵敏检测 S-腺苷同型半胱氨酸水解酶（SAHH）活性和抑制的简单比色法。FSN 稳定了 AuNPs，使其能够在高离子强度条件下存在，并且仅在存在同型半胱氨酸（HCys）和半胱氨酸时才会聚集。由于这个特点，在缺乏游离巯基的 S-腺苷同型半胱氨酸（SAH）存在下，FSN-AuNPs 被发现是分散的。在 SAHH 催化 SAH 水解后，产生的 HCys 分子通过形成 Au-S 键结合到 AuNPs 的表面。结果，通过每个 HCys 附着的 AuNP 之间的静电吸引导致 NP 聚集。这种方法的最小检测浓度为 100 单位/L（6 nM）。此外，由于腺苷类似物能够抑制 SAHH 活性，因此将腺苷类似物添加到含有 SAH 和 SAHH 的溶液中会抑制水解的 SAH 诱导的 NP 聚集。腺苷类似物的半最大抑制浓度（IC50）呈现出以下趋势：腺苷>单磷酸腺苷>二磷酸腺苷三磷酸腺苷。我们已经证明，SAHH 抑制和 FSN-AuNPs 的结合可用于选择性检测腺苷。
