Question

Helicobacter pylori, the bacterium responsible for gastric ulcers, can survive in the stomach (where the pH is as low as 1.5) in part because it synthesizes large amounts of the enzyme urease. (a) Write the reaction for urea hydrolysis by urease. (b) Explain why this reaction could help establish a more hospitable environment for H. pylori, which tolerates acid but prefers to grow at near-neutral pH.

Answer 1

Answer:

a) (NH₂)₂CO + H₂O ---> CO₂ + 2NH₃

b) The hydrolysis of urea by the urease enzyme generates ammonia which is a weak base. The ammonia thus produced, acts as a  base by accepting the hydrogen ions present in the acidic environment of the stomach. This reactions serves to neutralize stomach acid in order to create a suitable pH environment that the bacterium requires to survive and colonize.

Explanation:

a) Urease catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The equation of the reaction is shown below:

(NH₂)₂CO + H₂O ---> CO₂ + 2NH₃

b) The hydrolysis of urea by the urease enzyme generates ammonia which is a weak base. The ammonia thus produced, acts as a  base by accepting the hydrogen ions present in the acidic environment of the stomach. This reactions serves to neutralize stomach acid in order to create a suitable pH environment that the bacterium requires to survive and colonize.

The reaction of ammonia with hygrogen ions from HCl is shown below:

NH₃⁺ + H⁺ ----> NH₄⁺

Therefore, the continuous activity of the enzyme urease, helps to establish a more hospitable environment for Helicobacter pylori