TRFS-green 是用于检测活细胞中、硫氧还蛋白还原酶 (TrxR)、且具有高度选择性的、off−on 荧光探针。TRFS-green的最大吸收波长是 377 nm。
TRFS-green itself emits at ∼480 nm when excited at 377 nm.
TRFS-green displays a green fluorescence off−on change induced by the TrxR-mediated disulfide cleavage and subsequent intramolecular cyclization to liberate the masked naphthalimide fluorophore.
The fluorescence signal of TRFS-green in living cells was inhibited by pretreating the cells with TrxR inhibitor in a dose-dependent manner, potentiating the development of living cell-based screening assay for identifying TrxR inhibitors.
After incubating the cells with TRFS-green (10 μM) for 4 h, the bright green fluorescence appears.
TRFS-green shows no response to GSH or Cys, the predominant thiols in cells, or the endogenous reducing agents, such as vitamin C and NADPH.
TRFS-green is the first fluorescent probe of TrxR with a green emission. However, the response rate of TRFS-green to the enzyme is slow, and it takes more than 2 h to reach the maximal fluorescence signal even using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent.
