Gamma-glutamyl transpeptidase (or gamma-glutamyl transferase) (GGT) is a bacterial virulence factor that converts glutamine into
glutamate and ammonia, and converts glutathione into glutamate and cysteinylglycine. Helicobacter pylori GGT causes glutamine
and glutathione consumption in the host cells, ammonia production and reactive oxygen generation. These products induce cell-cycle
arrest, apoptosis, and necrosis in gastric epithelial cells. H. bilis GGT was shown to be a virulence factor decreasing host cell viability
by enhancing inflammatory stress response via oxidative stress in colon epithelial cells.
Tests applies to Helicobacter, Campylobacter and related species.
Make a no. 5 McFarland density suspension of cells.
Add 100 µl of bacterial suspension to a microtiter well containing 0.1 mg of L-glutamic
acid gamma (4-methoxy-beta-naphthylamide) (Sigma). Incubate for 4 hours at 37 ºC.
Reading the reaction: add 1 drop of cinnamaldehyde reagent (Innovative Diagnostics,
Negative if color is not changed, positive if color changes (need confirmation - admin
1. Dewhirst (F.E.), Seymour (C.), Fraser (G.J.), Paster (B.J.) and Fox (J.G.): Phylogeny of Helicobacter isolates from bird and swine feces
and description of Helicobacter pametensis sp. nov. Int. J. Syst. Bacteriol., 1994, 44, 553-560.
2. Sundus Javed, Raquel Mejías-Luque, Behnam Kalali, Christian Bolz, Markus Gerhard. Helicobacter bilis
Gamma-Glutamyltranspeptidase Enhances Inflammatory Stress Response via Oxidative Stress in Colon Epithelial Cells. August 23,
3. Vittorio Ricci, Maria Giannouli, Marco Romano, Raffaele Zarrilli. Helicobacter pylori Gamma-Glutamyl Transpeptidase And Its
Pathogenic Role World J Gastroenterol 2014 Jan;20(3):630-8.
(c) Costin Stoica