... again. 4. They are destroyed at high temperatures, as they are denatured by heat, most don't work at a temperature over 45o C, but there are always exceptions, some do work over this temperature. 5. Finally, they are sensitive to pH, most work best in neutral pH but, in the stomach acidic conditions are better and in the small intestine the enzymes work faster in alkaline conditions. Following on from point 2, the enzymes can only do one job because they have an active site, this is an area which locks onto the substrate and breaks it down. This active site can be changed. If the enzyme is exposed to extreme temperatures or pH the active site is damaged and doesn't fit onto the substrate, therefore not being able to react on it. There are optimum pHs and temperatures for the enzymes to work in. Hypothesis I am going to investigate how temperature ...

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