title: Prominent role of gamma-glutamyl-transpeptidase on the growth of Helicobacter pylori.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore 117597, Republic of Singapore.
authors.forename: Min
authors.initials: M
authors.lastname: Gong
authors.forename: Bow
authors.initials: B
authors.lastname: Ho
mesh_terms: D001881:Borates / Q000494:pharmacology; D015169:Colony Count, Microbial; D016480:Helicobacter pylori / Q000201:enzymology* / Q000254:growth & development*; D012694:Serine / Q000494:pharmacology; D005723:gamma-Glutamyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D001881:Borates; D012694:Serine; C010634:sodium borate; D005723:gamma-Glutamyltransferase