Re: how can you control the temperature in the reaction involving catalsase

Dear Madsci questioner,
Thanks for your question. As you know, endothermic reactions require energy to be supplied from the surroundings and this often results in a fall in temperature. A nice example is the dissolution of urea in water, where the solution becomes quite cold to the touch. There are a couple of things to consider here. First, remember that when investigating enzymatic reactions, very small amounts of both substrate and enzyme are used, generally in the micromolar or millimolar range. If you do some research, you can probably find out what the Gibbs free energy for the catalase reaction is, and knowing the concentrations of the components and some physical properties of water (eg specific heat capacity), you can probably make a good guess at what the decrease in the temperature of the reaction mixture will be. You may find that the change is small enough not to worry about.

However, when biochemists need to control reaction temperatures, they normally place the reaction tube in a water bath, the temperature of which is controlled by a thermostat. You may have access to one of these, or perhaps you can rig something up, perhaps using some of the equipment used in home brewing. There will be a slight lag time of course, as the reaction vessel equilibrates back to the set temperature, but the effects will probably be quite insignificant and this is about the best setup available for temperature control.

I hope this helps with your investigation,

Neil Saunders