Biochemistry
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For my A2 investigation I am looking at a kinetics reaction involving urea and urease and measuring the change in pH, I cannot find any useful information. Could you possibly point me in the direction of some helpful information?
Ulex writes
In a kinetics investigation it is never a good idea to monitor change of pH. This is because pH is a logarithmic function of concentration and changes very little with time - a pH change of 1 corresponds to a 10X change in concentration of H+!
The hydrolysis of urea produces ammonia which is a weak alkali and, as such, contains ions. During the reaction, therefore, the electrical conductivity of the solution increases. Measurement of this increase could form the basis of a method of following the reaction.
You might be able to remove samples of solution and titrate them with standard (very dilute) acid to measure the ammonia concentration as a function of time.
I have a nagging suspicion that the reaction might be self-inhibiting – i.e. the alkali produced inhibits the enzyme, which might prove to be a problem.
This is an interesting idea for an investigation. I suggest a Google search for practical ideas.
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Risk assessment
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updated: 11 November 2007
