ac6b01518_si_001.pdf (738.26 kB)
Download file

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

Download (738.26 kB)
journal contribution
posted on 16.06.2016, 00:00 by Sivaiah Areti, Surendra Kumar Verma, Jayesh Bellare, Chebrolu Pulla Rao
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.