Antibiotics in Action

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    Enzyme Specificity
    Activity #1

    Digestion of Protein by Tripsin

    In this portion of the investigation, the enzyme trypsin, produced in the pancreas (an organ that can secrete both enzymes and hormones), will be used to chemically “digest” proteins. The trypsin will be found in a pancreatic extract known as pancreatin. Other enzymes are present as well. To determine if the enzyme has catalyzed the reaction, you will look for the conversion of solid protein (gel) to a liquid.
    		Enzyme Specificity Menu

    Introduction
    Activity #1: Digestion of Protein
    by Tripsin
    Activity #2: Digestion of Lipids
    by Lipase
    Activity #3: Digestion of Starch
    by Amylase
    General Safety Guidelines
    Microbiology Safety Guidelines

    In this portion of the investigation, the enzyme trypsin, produced in the pancreas (an organ that can secrete both enzymes and hormones) will be used to chemically “digest” proteins. The trypsin will be found in a pancreatic extract known as pancreatin. Other enzymes are present as well. To determine if the enzyme has catalyzed the reaction, you will look for the conversion of solid protein (gel) to a liquid.

    Materials and Apparatus

    • Pancreatin solution (see formula)
    • Liquid gelatin (see formula)
    • Ice
    • 10-ml pipette, bulb
    • 10-ml graduated cylinder
    • Test tubes (25 x 200) with white marking patch

    Procedure

    Be sure to read the General Safety Guidelines and the Microbiology Safety Guidelines before beginning this lab activity.

    1. Label two test tubes #1 and #2, using a pencil on the white patch of the test tube.

    2. Using a pipet and aspiration bulb, measure 2.0 ml of distilled water into tube #1.

    3. With a second pipet, measure 2.0 ml of pancreatic extract solution into tube #2.

    4. To each test tube, add 10 ml of liquid gelatin measured in a 10-ml graduated cylinder.

    5. Place both test tubes in an ice bath for 20-30 minutes.

    6. After the cooling time has elapsed, place a small piece of cellophane wrap and your thumb over the top of each tube. Invert each tube to determine if the gelatin has set (gel state).

    Data Analysis

    If there are differences, explain these different results, based on the contents of each tube and the chemistry of enzyme action on protein.

     

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