Ok so you are knowlegeable regarding enzymes. Maybe kill was the wrong choice of words.
Enzymes will do their job over the range of temperatures prevalent in the cell environment. For living organisms this is body temperature. If it gets too hot, however, an enzyme may no longer be able to help reactions occur. This is because at higher temperatures the protein molecule that is the enzyme may start to 'unravel' as its bonds break, and its surface may no longer be the correct shape for the substrates to fit. At approximately 190 degrees F the formula will cease to work properly with the given enzyme content.