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Catalase in Potatoes - Disk method
Introduction
Catalase is found in animal and plant tissues, and is especially abundant in
plant storage organs such as potato tubers, corms, and in the fleshy parts of fruits. You will isolate
catalase from potato tubers and measure its rate of activity under different conditions. A glass, fiber
filter will be immersed in the enzyme solution, then placed in the hydrogen peroxide substrate. The
oxygen produced from the subsequent reaction will become trapped in the disc and will give it
buoyancy. The time measured from the moment the disc touches the substrate to the time
it reaches the surface of the solution is a measure of the rate of the enzyme activity.
Materials: 50mL blended Potato solution, distilled water in squirt bottle containers, ice, filter paper, Salt (cheap), forceps, 100 mL - 1.0% H2O2, hole punch
Directions
Rinse forceps in distilled water and dry with paper towel.
2. Use clean forceps to immerse a glass-fiber filter disc in your full-strength enzyme solution. Allow the disc to absorb the catalase solution for 5 seconds, then remove and drain by touching the edge to a paper towel for 10 seconds.
3. Drop the disc into the containing the 1% hydrogen peroxide solution beaker. Begin your timer at the moment the disc is introduced to the substrate. The disc should sink rapidly to the bottom of the beaker. Rinse forceps again.
4. After a few moments, oxygen produced by the catalase-catalyzed reaction will cause the disc to rise. Stop your timer at the moment the disc rises to the surface of the substrate beaker. Remove and discard the disc. Save the substrate solution.
5. Record the time to rise in seconds.
Catalase in Potatoes - Liver/Yeast method
Trypsin and Gel plates
Materials: 150mL 0.5% trypsin solution,150mL distilled water (100mL extra for precaution), holes mold, 1x stirring rod,glass beakers (± 15mL), pipette, plastic petri dishes,gelatin, graduated cylinder (± 0.01mL)
Procedure
To create the gelatin plates put 12 grams of pure gelatin with 72 mL of cold water. Simmer it on a low heat until the gelatin dissolves. Then pour it into the respective 6 petri dishes and cool it in the fridge for several hours.
Take a pipette and draw up 0.15mL of the 0.5% trypsin solution into each hole.
After two days measure the diameter of the holes, which should have gotten biggre
Pectinase and Apples
Introduction
Pectinases are enzymes that breakdown the polysaccharide pectin which is located primarily in the middle lamella of cell walls. Pectin compounds are widely distributed in plant tissues, especially in fruits. They are large, colloidal molecules which are responsible for holding dispersed particles in suspension in fruit juices. In addition to influencing the amount of suspended particles in a juice, pectins also increase the viscosity of the juice. The presence of suspended particles in tomato and orange juice is not undesirable to most people, however, “clear” juices such as apple and grape are more often preferred. Commercially prepared pectinase can be added to prepared fruits in order to hasten the release of juice and aid in the “settling out” of suspended particles in fruit juice.
Material: Funnels (2) Graduated cylinders, 100-ml (2) Beakers, 50-ml (2) Pipets or syringe, to measure 0.5 ml liquid (2) Spatulas or spoons (2) Apple sauce Distilled water (10 ml) Pectinase (available from several biological supply companies or businesses providing cider and/or wine making supplies) Wax pencil Procedure
1. Place approximately 25 ml of apple sauce into each of the two beakers labelled “no enzyme” and “pectinase”.
2. Add 0.5 ml distilled water to the “no enzyme” beaker and 0.5 ml pectinase to the “pectinase” beaker.
3. Stir the contents of each beaker thoroughly (using separate spatulas).
4. Let stand 10 minutes or longer.
5. Place cheesecloth in a funnel and place the funnel into the graduated cylinder.
6. With the aid of the spatula, pour contents of each beaker into a separate funnel and collect filtrate.
7. Record the amount of juice collected in each cylinder.
Results The volume of filtrate from the apple sauce plus pectinase is usually at least double that of the filtrate without the enzyme.