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    Substrate Catechol (also known as pyrocatechol and 1,2-dihydroxybenzene)
    Substrate Catechol (also known as pyrocatechol and 1,2-dihydroxybenzene)Substrate Catechol (also known as pyrocatechol and 1,2-dihydroxybenzene)Substrate Catechol (also known as pyrocatechol and 1,2-dihydroxybenzene)
    Substrate Catechol (also known as pyrocatechol and 1,2-dihydroxybenzene)
    Apple on left was swabbed with lemon juice. Apple on right was not. Note accumulation of brown benzoquinone.

    Enzyme Class Experiment: 
    Catechol Oxidase & Accumulation of Polyphenol in Apples
    (How to Prevent Apples From Browning)
     
    CLASS NOTES from Science Prof Online

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    Instructor's Corner
    How Enzymes Work
    Unlike inorganic catalysts, enzymes are very specific organic molecules. Each type of enzyme acts on only one particular compound, known as its substrate. The substrate briefly binds with the enzyme, and, in the process, is changed.

    Each enzyme has a unique three dimensional shape, including a surface groove called an active site. The active site fits its target substrate much like a key fits in a lock. Other substances that don’t fit can't enter the active site, so no reaction occurs. If the shape of an enzyme’s active site is altered, the enzyme can no longer work, and therefore is considered to be denatured.

    How to Prevent Fruits & Vegetables From Browning
    Catechol oxidase (also known as catecholase) is an enzyme present in most fruits and vegetables. It facilitates the browning of cut or bruised produce by catalyzing a reaction between the substrate molecule catechol and atmospheric oxygen (O2). The ultimate product of this oxidation reaction is polyphenol, a brown compound that accumulates when fruits and vegetables are exposed to air. This color change is especially apparent in produce that has white flesh, such as apples and potatoes.

    Enzymes are biological catalysts; proteins that help speed up the chemical reactions necessary for life. 
     animation from McGraw-Hill.

    The intermediate product benzoquinone continues to spontaneously react to ultimately form the brown product polyphenol.
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    •  and quiz from Life: The Science of Biology.
    • ” from Enzymedica. These guys are selling supplements. I don’t endorse the supplement, but their video is very instructive regarding enzymes and digestion.
    • ” from HowStuffWorks, a Discovery 中国福利彩票下载安装αpp.
    •  animation from Pearson Prentice Hall.
    •  - song by MABS Music

    FREE study questions to help students better understand  and