Selenocysteine vs Cysteine: Tuning the Derivatization on Benzenesulfonyl Moiety of a Triazole Linked Dansyl Connected Glycoconjugate for Selective Recognition of Selenocysteine and the Applicability of the Conjugate in Buffer, in Serum, on Silica Gel, and in HepG2 Cells

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• 作者：Sivaiah Areti ; Surendra Kumar Verma ; Jayesh Bellare ; Chebrolu Pulla Rao
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：July 19, 2016
• 年：2016
• 卷：88
• 期：14
• 页码：7259-7267
• 全文大小：703K
• 年卷期：0
• ISSN：1520-6882

文摘

A dansyl derivatized triazole linked glucopyranosyl conjugate (^NO2L) has been synthesized and characterized and was used in the present study. The conjugate ^NO2L releases a fluorescent product upon reaction by Cys-SeH in aqueous PBS buffer by exhibiting a ∼210-fold fluorescence enhancement even in the presence of 20 other amino acids with a minimum detection limit of (1.5 ± 0.2) × 10^–7 M. The selectivity of the Cys-SeH to ^NO2L was further proven by extending the fluorescence study to different other selenium compounds. The role of para-nitrobenzenesulfonyl (pNBS) center in ^NO2L in the selective recognition of Cys-SeH was confirmed when the fluorescence emission studies were carried out using five different derivatizations possessing two NO₂, five fluoro, two fluoro, one fluoro, and no fluoro groups. The nucleophilic substitution reaction of Cys-SeH on ^NO2L has been clearly demonstrated on the basis of ¹H NMR, ESI-MS, and absorption spectroscopy, and the heat changes were monitored by isothermal titration calorimetry. The application potential of ^NO2L has been demonstrated by studying its selectivity toward Cys-SeH in aqueous PBS buffer, in bovine serum, and on the silica gel surface that lead to minimum detection limits of (25 ± 2), (80 ± 5), and (168 ± 16) ppb, respectively. The biological applicability of ^NO2L for Cys-SeH was further demonstrated in HepG2 cells by fluorescence microscopy. Thus, ^NO2L is aqueous soluble and a biologically acceptable probe for Cys-SeH.