温度对酶活性的影响enzyme activity

Put 2 ml of amylase inhibitor solution into tube 2
Keep the tube 3 as before
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Step 3
Into each of three more boiling tubes put 2 ml amylase solution.
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Step 6
Replace the tubes in the water bath at 370 C and measure the time taken for the blue/black colour to disappear.
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Step 7
Test for sugar: add 1ml Benedict’s solution to each boiling tube and heat for 5 minutes.
Dr. A. K. M. Arif Uddin Ahmed.
Lecturer, Department of Pharmacology & Biochemistry.
Medical College of Xiamen University, China Next
28
Materials required
2
Prodedure Step 1
28°C
37°C
Set up five water baths at different temperatures, e.g. 0°C, 28°C, 37°C, 55°C, 80°C.
3
Step 2
Into each of five boiling tubes put 5 ml starch solution and 3 drops potassium iodide (I2-KI) solution.
4
Step 3
Into each of five more boiling tubes put 2 ml amylase solution.
5
Step 4
28°C 37°C
Place a pair of boiling tubes into each water bath and leave for 5 minutes.
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Step 7
Test for sugar: add 1ml Benedict’s solution to each boiling tube and heat for 5 minutes.
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Step 8
A brick red colour indicates a reducing sugar is present.
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Step 1
Into each of five boiling tubes put 5 ml starch solution and 3 drops potassium iodide (I2-KI) solution.
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Step 2
Put 3 drops of dilute HCL into tube 1 Put 1 drop of dilute HCL into tube 2
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Step 8
A brick red colour indicates a reducing sugar is present.
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Step 9
Repeat the whole experiment with boiled amylase as a control.
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Expected result
Biochemistry Practical
2) a) The effects of temperature, on the enzyme activity
Investigate the effect of temperature on amylase activity
Next
1
Materials required
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Step 1
Into each of three boiling tubes put 5 ml starch solution and 3 drops potassium iodide (I2-KI) solution.
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Step 2
Put 2 ml of Water into tube 1
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Step 4
Place all boiling tubes into water bath at 370 C and leave for 5 minutes.
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Step 5
Pour the amylase into the tube of starch solution and gently shake.
The enzyme works best at pH 7. The blue / black colour faded and Benedict’s resulted in a positive test.
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Table of Results
pH Time taken for solution to turn colourless Test for sugar
10
Step 9
Repeat the whole experiment with boiled amylase as a control.
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Expected result
The enzyme works best at 37OC. The blue / black colour faded and Benedict’s resulted in a positive test.
Put 10 drops of water into tube 3
Put 1 drop of dilute Na2CO3 into tube 4 Put 3 drops of dilute Na2CO3 into tube 5
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Step 3
Into each of five more boiling tubes put 2 ml amylase solution.
Lecturer, Department of Pharmacology & Biochemistry.
Medical College of Xiamen University, China Next
15
Materials required
1. Water bath 2. Stirrer 3. Laboratory Thermometer 4. pH meter / pH paper 4. Beaker 5. Measuring cylinder 6. Boiling tube 7. Stop watch 8. Starch solution (2mg/ml) 9. Amylase solution (0.5 mg/ml) 10. Potassium iodide (I2-KI) solution 11. Benedict’s solution 12. HCL (1 mol/L) 13. Na2CO3 (0.1 mol/L)
6
Step 5
Pour the amylase into the tube of starch solution and gently shake. Repeat for each temperature.
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Step 6
28°C
37°C
Replace the tubes in the water bath and measure the time taken for the blue/black colour to disappear.
12
Table of Results
Temperature (°C) Time taken for solution to turn colourless Test for sugar
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Principle of Benedict’s test
Benedict's reagent is used as a test for the presence of reducing sugars. This includes all monosaccharides and many disaccharides, including lactose and maltose. Benedict's reagent contains blue copper(II) ions (Cu2+) which are reduced to copper(I) ions (Cu+). These are precipitated as red copper(I) oxide which is insoluble in water. Benedict's Reagent provides a semi quantitative test for reducing sugars along with qualitative test. The color of the obtained precipitate gives an idea about the quantity of sugar present in the solution. A greenish precipitate indicates about 0.5% concentration; yellow precipitate indicates 1% concentration; orange indicates 1.5% and red indicates 2% or higher concentration.
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Step 6
Replace the tubes in the water bath at 370 C and observe the disappearance of the blue/black colour in tube 1 and tube 3. When the blue/black cnd tube 3, then take out all three tubes from water bath.