Discriminating three biothiols by using one fluorescent probe

摘要

A 1,1'-bi-2-naphthol (BINOL) based dialdehyde (R)-1 is found to exhibit selective fluorescent response towards cellular thiols, (L)-Cys, (L)-Hcy, and GSH. (R)-1 reacts with (L)-Trp to form a Schiff base 2 which quenches the emission of (L)-Trp at lambda = 340. Coordination of 2 with Zn(II) leads to greatly enhanced emission at lambda = 530 nm. When the in situ generated 2 from the combination of the solution of (R)-1 (1.0 x 10(-5) M) + Trp (2 equiv) +Zn(OAc)(2) (2 equiv) is treated with (L)-Cys, (L)-Hcy, and GSH, different fluorescent responses at three emission wavelengths, including 340, 421 and 530 nm, are observed. This allows the in situ generated 2 to be used as a ratiometric fluorescent probe to discriminate these three biothiols. NMR study of (R)-1 with (D)- or (L)-Cys in the presence of Zn(II) shows that the unique reactivity of Cys provides basis for the selective ratiometric fluorescent response. (R)-1 + Zn(II) also exhibits enantioselective fluorescent response toward (D)- and, (L)-Cys. (C) 2018 Elsevier Ltd. All rights reserved.