Amyloid beta is a large precursor protein in the cell

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Amyloid-beta is a large precursor protein in the cell. Clearly linked to Alzheimer s disease creating senile plaques. Starts in the hippocampus and moves up. Neurodegenerative protein aggregation Alzheimer s disease, the most common neurodegenerative disease. The formation of aggregated amyloid- beta fibers is another characteristic of Alzheimer's disease, but neurodegeneration and memory loss can be detected before amyloid fibers accumulate in the brain. Molecules that help denatured proteins in folding. (ie. sickle cell) molecular chaperones - and they bind to the newly made polypeptide and enable proper folding. Ensuring proper protein folding is vital because proteins that do not fold properly   often due to genetic mutations that substitute one amino acid for another   can lead to a variety of diseases. Levels of protein structure (3-dimensional shape of polypeptide) Primary = amino acid chain, Covalent bond (strong), does not denature. Secondary = alpha helix & Beta sheet, H bond, denatured by salt and ph change, contain carboxyl group and amino groups. Hydrogen bonds formed from 2 polar amino acids! Tertiary = side chain interaction, (R-group) Changes seen with increased temp, salt, change in pH and reducing agents. ex. sickle cell, arthritis, hemophilia. Quaternary Subunit = more than one polypeptide, Changes seen with increased temp. Hbg What structure would be unaffected by complete denaturation of multi-subunit Tertiary structure is hydrophobic. Protein structure is stabilized primarily by the hydrophobic effect, disruption of the hydrophobic effect is the simplest way to denature a protein this is done by heating it up. Methotrexate treatment in cancer, possible affects enzyme activity . and APC gene decreased expression because of Methyl group. Methotrexate works by blocking an enzyme process in cancer cells so they cannot grow. APC is classified as a tumor suppressor gene . Substrate enzyme complex - like a lock and key Substrate binds to an active site, producing an enzyme-substrate complex. The geometric and the chemical complementarity between the enzyme and substrate depend on noncovalent forces. Know substrates, enzymes, products and inhibitors. substrate is a molecule that an enzyme will bind preferentially to any other molecule, and each enzyme is specific for that substrate, it won't react with molecules that are not its substrate. active site , which serves as the binding platform for its specific substrate(s) and acts as the site of the chemical reaction. Induced fit Substrate and active site are somewhat complementary prior to substrate binding, enzymes will adjust their active site conformation slightly as the substrate binds to improve the fit . When the molecule is
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BIO-Chemistry Study Guide OA1 recognized as the substrate, the enzyme will adjust to form itself around the substrate more tightly to facilitate the reaction is catalyzes.
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