Here is an experiment to demonstrate the activity of salivary enzyme amylase.
Principle:
Enzyme amylase is found in saliva, which is secreted by salivary glands in mouth palate. Amylase partially hydrolyses (breaks) starch or glycogen into glucose and maltose. Salivary amylase acts at a temperature of 37°C and a pH of 6.6 (acidic).
When iodine solution is mixed with starch, blue colour is obtained. When starch is first hydrolysed with amylase and then mixed with iodine solution, blue colour is not obtained because starch has been broken into glucose and maltose.
ADVERTISEMENTS:
Requirements:
Beakers (100cc), pipettes, test tubes, glass-stoppered bottles, plain or cavity slides, staining tubes, cavity blocks (small), toluene, starch paste, 0.02 N iodine solution, incubator set at 37°C.
Procedure:
1. Clean all glass apparatuses first with vim. Dry them and then rinse with potassium dichromate sulphuric acid solution. Wash glass apparatuses 9 times with tap water and 3 times with distilled water. In case chromic acid solution is not available wash them with vim, tap water and then with distilled water. Let all the apparatuses become dry. Keep them inverted over blotting paper for 24 hours.
ADVERTISEMENTS:
2. Prepare 0.02 N iodine solutions in a glass stoppered bottle.
3. Prepare 1 per cent starch solution (1 gram of starch powder + 100 cc.) of distilled water in a glass stoppered bottle.
4. For collecting own saliva, rinse your month with warm water quickly. Then take 20-25 cc of warm water in mouth, rotate water with tongue for 2-3 minutes and collect the saliva solution in a beaker. This contains salivary enzyme amylase.
5. In another beaker mix 5 cc of 1 per cent starch solution and 5 cc of saliva solution. Incubate the beaker in an oven set at 37°C for one hour.
ADVERTISEMENTS:
6. Take two cavity blocks or staining tubes and mark them A and B, respectively with glass marking pencil. In each cavity block or a staining tube, add 2 drops of iodine solution. In cavity block A add a drop of starch-saliva mixed solution with a pipette. With another pipette add a drop of starch solution only in cavity block B.
Result:
In cavity block B, solution becomes blue while in cavity A it remains colourless as starch has been hydrolysed into glucose and maltose demonstrating activity of enzyme amylase.