Unit 3 enzymology and catalytic mechanism 1 there is

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UNIT 3: ENZYMOLOGY AND CATALYTIC MECHANISM 1. There is a question about methotrexate treatment in cancer, I think the question wanted to know how it affects enzyme activity. ---- methotrexate works by blocking an enzyme process in cancer cells so that they cannot grow (The enzyme dihydrofolate reductase catalyzes a step-in nucleotide synthesis from folic acid. The medication methotrexate has a similar structure as folic acid and is used as a chemotherapy agent to inhibit cancer growth. What effect does
2. Induced fit
Know about substrate enzyme complex- like lock and key
o Which region describes the active state of an enzyme?
Know about substrates, enzymes, products, and inhibitors: 2 questions w/ pictures you must identify these o Substrate : molecule that an enzyme will bind preferentially to any other molecule. Each enzyme is specific for that substrate, it won’t react with molecules that are not its own substrate. Increase substrate increase reactions o Active site : enzymes have an active site, which serves as the binding platform for its specific substrates and acts as the site of the chemical reaction. o Allosteric site : any site OTHER THAN the active site Know what substrate | enzymes | active site look like on diagram Substrate enters active site of enzyme. 1. Enzyme/substrate complex slight change in shape. 2. Enzyme/products complex change in color. 4. Product released. Enzyme inhibition (competitive vs non-competitive) Competitive- inhibitor- usually a molecule SIMILAR in structure to a substrate that can bind to an enzyme’s ACTIVE SITE even though the molecule is UNABLE TO REACT! Competitive inhibit----medications. competitive inhibitor competes with active site. Increase substrate increase reaction, can be reversed. Non-competitive inhibitor- some non-competitive inhibitors attach to the enzyme at the allosteric site (a site other than the active site) Allosteric binds elsewhere and it lasts longer and is harder to reverse. Feedback inhibition (non-competitive ) - know that once the end product builds up it will bind to the allosteric site on the first enzyme to stop (or inhibit) the pathway!! Meaning it binds to the enzyme to slow the making of the product.

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