B2 - Investigating Enzymatic Reactions

What is the method for investigating the effect of pH on enzyme activity?

Put a drop of iodine solution into every well of a spotting tile. Set up a water bath and heat it to 35°C. Try to keep the temperature of the water constant throughout the experiment. Use a syringe to add 1cm³ of amylase solution and 1cm³ pH 5 buffer solution to a boiling tube. Using test tube holders, put the tube into the water bath and wait for five minutes. Next, use a different syringe to add 5cm³ of a starch solution to the boiling tube. Immediately mix the contents and start a stop clock. Use continuous sampling to record how long it takes for the amylase to break down all of the starch. To do this, use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. When the iodine solution remains browny-orange, starch is no longer present. Repeat the whole experiment with buffer solutions of different pH values to see how it affects the time taken for starch to be broken down.

How do you calculate the rate of reaction in the pH enzyme experiment?

$$rate=\frac{1000}{time}$$

What is a rate?

How much something changes over time.

How do you measure the rate of change?

$$rate=\frac{\operatorname{ch}ange}{time\cdot taken}$$