Group A -Amylase Lab


Part A. Measuring the amount of maltose present

1. Select five test tubes, label A1 through A5. Be sure they are labeled with a permanent marker.

2. Place these test tubes in the test tube rack.

3. Using the pipette pump dispenser, add 1 ml of amylopectin solution, 1 ml of DNS reagent and 1 ml of tartrate solution to each tube. Caution: DNS reagent should be washed off your skin immediately. Check off each chemical in the table below as you add it.

Test tube #
Amylopectin
DNS Reagent
Tartrate Solution
Maltose
DI Water
A1
1 ml

.

1 ml

.

1 ml

.

0 µl

.

1000 µl

.

A2
1 ml

.

1 ml

.

1 ml

.

200 µl

.

800 µl

.

A3
1 ml

.

1 ml

.

1 ml

.

400 µl

.

600 µl

.

A4
1 ml

.

1 ml

.

1 ml

.

800 µl

.

200 µl

.

A5
1 ml

.

1 ml

.

1 ml

.

1000 µl

.

0 µl

.

4. Using an adjustable pipettor, add amounts of maltose solution and distilled water to each tube as indicated by the table above. Check off each one as you add it.

5. Mix the contents of each tube using the vortex mixer. Check off this step in the table below as you complete it.

Test Tube #
Vortex Mixer ()
Hot Water Bath ()
Absorbance Measured
A1

.

.

.

A2

.

.

.

A3

.

.

.

A4

.

.

.

A5

.

.

.

6. Place your tubes into a hot (95oC- use caution) water bath for five minutes.

7. Remove the tubes from the water bath, return to your lab station and allow them to cool to room temperature. Observe and make note of the color change - use color pencils if available. Store tubes in the refrigerator until next lab period if necessary.

Next Day or if time permits:

8. Take your samples to the spectrophotometer. Measure the absorbance at a wavelength of 540 nm of the contents of each tube. Record the absorbance in the above table. Your teacher will provide instructions on the use of the spectrophotometer. The absorbance is proportional to the amount of maltose present.

9. Prepare the graph of absorbance versus volume of maltose solution added as indicated in the worksheet.


Go to directions for Part [B] [C] [D]