[Allete]

Hello, my name is Allete.
A week ago we had finished an experiment about the effects of temperature and pH on salivary amylase, I already passed my report about it. However, my teacher had one question that we weren't able to answer. It was about the results of our experiment. We know that the optimum temperature of Salivary Amylase is 37˚C(the body temperature). Any temperature higher than that, the structure of Salivary Amylase is denatured because more kinetic energy is applied. Kinetic energy makes the molecules vibrate and collide with each other. The more the kinetic energy, the more times the molecules collide with each other and this destabilizes the structure.

However during our class' experiment, our results were different.

The class was divided into groups, and each group was assigned one temperature and one pH. The temperatures we used were 4˚C, Room Temperature, 37˚C, 50˚C, and 70˚C.

Here are the results.



As you can see the optimum temperature in our experiment is 50˚C and that the reaction time for the 37˚C is even slower than what was recorded for the room temperature (32˚C). We looked for any possible errors in the way on how we did the experiment.
We do know that:
•The saliva for the enzyme solution used for the whole class was gathered from one person only, he also has a fast metabolism.
•The water bath for the 37˚C was set up by the lab technicians and was maintained in that temperature for the whole duration of the class, we even used it for the effect of pH.
We argued that the test tube used for the 37˚may not have been washed properly, or that the group who did the experiment made a mistake but my teacher won't accept them as valid. We tried looking for other possible errors but we can't find any more.

My question is that what are other factors that can affect the reaction time of Salivary Amylase when it is at optimum temperature?

[fledarmus]

Why didn't you believe the data that you obtained?

See the graph on page 132, here: http://jdr.sagepub.com/content/30/1/130.extract

[Allete]

Sorry, I can't. It says I need to register and pay for my access.
So the reaction is right? Or that Salivary Amylase still reacts at a temperature of 50˚C but the results for 37˚C is wrong?

[fledarmus]

They report a graph very similar to yours, although the axes are set up differently, and they report a plateau between 30C and 37C rather than an actual drop. For further information you should do a literature search. I'm sure there are other examples that you can access through your university library.

[Allete]

Thank you! I'll do that. I'll try using my college's library. I know they have access to sites like the one you replied with.

[Babcock_Hall]

Many enzymes would behave in a qualitatively similar way.  They increase in rate as temperature rises, but if they denature, the rate falls.  Denaturation is a complicated process, and any difference in conditions, such as the length of time the enzyme spends at a given temperature, pH, ionic strength, might affect the rate at which an enzyme denatures.  So different workers might get slightly different results unless these variables are completely controlled.  The difference between 32 °C and 37 °C might be experimental error of some sort.  Exactly how are you measuring the rate?