Purification of surface-associated urease from Helicobacter pylori

Helicobacter pylori colonizes the human gastric mucosa and produces large a mounts of urease. The enzyme was extracted from the bacteria by distilled w ater and purified by gel-permeation (Sephacryl S-300), anion-exchange chrom atography (Mono Q) and a second gel-permeation (Superdex 200). Urease enzym e activity was detected with a spectrophotometic assay based on phenol red. The optimal pH for anion-exchange was 6.9. The recovery of urease was 55-7 5%, purity 93-98% and the overall protein recovery 0.8-1.4%. The urease in the final extract still had enzymatic activity and showed the typical subun its of M-r 66000 and M-r 30000 when subjected to sodium dodecyl sulfate-pol yacrylamide gel electrophoresis. (C) 2000 Elsevier Science BN, All rights r eserved.