γ glutamyl transferase assay kit

Serum and tissue GGT activities were tested by the γ-Glutamyl transferase Assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China). The concentrations of T-GSSG, GSSG, and GSH in serum and tissue were measured with the GSH/GSSG assay kit (Beyotime, Beijing, China). As for measurement in tissue lysates, the concentrations of T-GSSG, GSSG, and GSH were normalized by the protein concentrations of tissue lysates. The serum and tissue total oxidization capacities were assayed with a Total Antioxidant Capacity Assay Kit (Beyotime, Beijing, China).

The levels of total cholesterol (TC), triglyceride (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyl transpeptidase (γ-GT) in serum were accessed by an automatic biochemistry analyser (Hitachi, Japan) according to the manufacturer’s instructions. In addition, the levels of TC, TG, AST, ALT, and γ-GT in liver tissues were detected using Total cholesterol assay kit (Nanjing Jiancheng Bioengineering Institute, China), Triglyceride assay kit (Nanjing Jiancheng Bioengineering Institute, China), Aspartate aminotransferase Assay Kit (Nanjing Jiancheng Bioengineering Institute, China), Alanine aminotransferase Assay Kit (Nanjing Jiancheng Bioengineering Institute, China), and γ-glutamyl transferase Assay Kit (Nanjing Jiancheng Bioengineering Institute, China), respectively.

COS7 cells were cultured in high-glucose DMEM supplemented with 100 U/mL of penicillin, 100 μg/mL of streptomycin, and 10% FBS in 5% CO2, in a 37°C incubator. Approximately 1 × 10⁴ cells were plated and transiently transfected with 0.5 μg of pcDNA3.1-ggt1-KOZg or pcDNA3.1-ggt1-KOZa using Lipofectamine® LTX Reagent (Invitrogen Corp., Carlsbad, CA, USA) according to the manufacturer's protocol. After 48 hours, the cell culture mediums were collected. Then, the cells were scraped off the plate and lysed immediately with PBS followed by determination of protein concentration with a Thermo Scientific Pierce BCA Protein Assay Kit. The culture mediums and the cell lysates were subjected to detect GGT activity using a γ-Glutamyl transferase Assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China).