Abstract
AIM: gamma-glutamyl transpeptidase (GGT) has been reported as a virulence and colonizing factor of Helicobacter pylori (H pylori). This study examined the effect of GGT on the growth of H pylori. METHODS: Standard H pylori strain NCTC 11637 and 4 clinical isolates with different levels of GGT activity as measured by an enzymatic assay were used in this study. Growth inhibition and stimulation studies were carried out by culturing H pylori in brain heart infusion broth supplemented with specific GGT inhibitor (L-serine sodium borate complex, SBC) or enhancer (glutathione together with glycyl-glycine), respectively. The growth profiles of H pylori were determined based on viable bacterial count at time interval. RESULTS: Growth was more profuse for H pylori isolates with higher GGT activity than those present with lower GGT activity. However, in the presence of SBC, growth of H pylori was retarded in a dose dependent manner (P = 0.034). In contrast, higher growth rate was observed when GGT activity was enhanced in the presence of glutathione and glycyl-glycine. CONCLUSION: Higher GGT activity provides an advantage to the growth of H pylori in vitro. Inhibition of GGT activity by SBC resulted in growth retardation. The study shows that GGT plays an important role on the growth of H pylori.