Sensitive Fluorescence Probe with Long Analytical Wavelengths for γ-Glutamyl Transpeptidase Detection in Human Serum and Living Cells

Abstract

A new sensitive fluorescent probe with long analytical wavelengths for γ-glutamyl transpeptidase (GGT) assay has been developed by incorporating the γ-glutamyl group as a recognition unit into the fluorophore of cresyl violet (CV). The detection mechanism is based on the GGT-catalyzed cleavage of the γ-glutamyl group, followed by the release of CV, which leads to a distinct color change from light yellow to pink and a large fluorescence enhancement at 615 nm (λex = 585 nm). Under the optimized conditions, the fluorescence intensity of the probe is directly proportional to the activity of GGT in the range of 1-50 U/L with a detection limit of 5.6 mU/L. By virtue of its high sensitivity and long analytical wavelengths, the probe has been used to directly determine GGT in human serum samples from both healthy people and liver cancer patients, and the obtained results accord well with those acquired by commercial GGT fluorometric assay kit. The probe has also been employed to image endogenous GGT in living cells. Notably, with our probe the expression level of GGT in HepG2 cells under the action of sodium butyrate (an anticancer drug) was studied by fluorescence confocal microscopy, revealing that sodium butyrate can induce the upregulation of GGT in HepG2 cells in a dose- and time-dependent manner. This behavior of sodium butyrate has further been confirmed by lysate assay and inhibitor experiment. The proposed probe is rather simple and may find a wide use in the determination of GGT in clinical and biological samples.

Recent Advances in the Development of Optical Imaging Probes for γ‐Glutamyltranspeptidase

“…In 2015, Ma and co‐workers took the widely used fluorophore of Cresyl Violet to design a sensitive off–on fluorescence probe ( 7 ), which showed a significant (ca. 500‐fold) fluorescence enhancement at λ =615 nm ( λ ex =585 nm) upon reaction with GGT . Studies on the detection sensitivity toward GGT revealed that 7 was highly sensitive to detect GGT, with a detection limit of 5.6 mU L −1 GGT.…”

Observation of the Generation of ONOO– in Mitochondria under Various Stimuli with a Sensitive Fluorescence Probe

“…[13][14][15][16][17][18][19][20] In the past several years, a number of fluorescence probes were developed to detect ONOOby usually taking advantage of the strong oxidizability and nucleophilicity of ONOO -. They mainly include the phenyl boronic ester-based, 21,22 hydrazine-based, 23,24 selenium or tellurium-based [25][26][27] and methyl(4hydroxyphenyl)amino-based probes.…”

Intraoperative imaging of hepatic cancers using γ-glutamyltranspeptidase-specific fluorophore enabling real-time identification and estimation of recurrence

“…In order to visualize GGT activity in living samples, several GGT-activatable fluorescent probes have been developed x,y . Among these probes, we focused on our previously developed γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), which enables in vivo identification of cancer tissues 11, 12 . gGlu-HMRG is nonfluorescent in its native state but is rapidly hydrolyzed by GGT to generate HMRG, which emits fluorescence with a peak wavelength of ~520 nm 12 .…”