This work builds on our previous findings [21] on the cell-cycle inhibiting effect of H. pylori BCF on HDF and epithelial cell lines derived from human gastric tumours with different levels of differentiation (AGS, MKN28, MKN74 and MKN7), and focuses on the isolation and characterisation of L-asparaginase as the factor responsible for cell-cycle inhibition. The gene discussed is ASPG; the disease is gastric neoplasm.