Bio 1510 – Enzymes Lab Procedure

This week you will use an online simulator to perform the experiments in your lab manual. You will test effects of various conditions on enzyme function: temperature, pH, and substrate concentration. You will not perform part 3 (Effects of Denaturation).

To complete the weekly lab participation exercise you should follow along with the procedure in your lab manual using the simulator and the changes detailed below. Then fill in the data tables and graphs on pgs. 55 – 69 and answer the questions on pgs. 59 – 60 in the lab manual. You will use these data to write your lab report so be sure to collect accurate data.

The simulator uses lactose as the substrate and lactase as the enzyme (as opposed to sucrose and sucrase in the lab manual). Refer back to Lab 2B: Carbohydrates for more information on carbohydrates and the Benedict’s test. The Benedict’s test will show how much glucose is produced when lactase breaks lactose into glucose and galactose.

Procedure:

Open the online simulator: https://sites.google.com/site/biologydarkow/lactase-enzyme-simulation

Part 1 – The effect of temperature on enzyme activity

• Set the amount of initial lactose to 300 mg/dl
• Set the pH to 7.0
• Run the simulator at 0° C, 25° C, 37° C, 55° C, and 100° C
• Use the table below to record your data

             Table 3.1 – Effect of temperature on enzyme activity

Either hand-draw (neatly!) or use Excel/Sheets to create graphs based on the data in your table. Paste your graph below:

Part 2 – The effect of pH on enzyme action

• Set the amount of initial lactose to 300 mg/dl
• Set the temperature to 37° C
• Run the simulator at pH 3, 5, 7, 9, and 11
• Use the table below to record your data

             Table 3.2 – Effect of pH on enzyme activity

Either hand-draw (neatly!) or use Excel/Sheets to create graphs based on the data in your table. Paste your graph below:

Part 3 – The effect of denaturation on enzyme activity

• We will skip this portion of the experiment

Part 4 – The effect of substrate concentration on enzyme activity

• Set the temperature to 37° C
• Set the pH to 7.0
• Run the simulator using initial lactose concentrations of 0 mg/dl, 200 mg/dl, 400 mg/dl, 600 mg/dl, 800 mg/dl, and 1,000 mg/dl
• Use the table below to record your data

             Table 3.4 – Effect of substrate concentration on enzyme activity

Either hand-draw (neatly!) or use Excel/Sheets to create graphs based on the data in your table. Paste your graph below:

Use the space below to answer the questions on pgs. 59 – 60 in your lab manual.