Slides 6 013112(1)

Slides 6 013112(1) - Lecture overview We are now discussing...

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Lecture overview We are now discussing features of protein function Last lecture: Protein binding: how proteins interact with other molecules and other proteins to enable function Example: transport of oxygen by hemoglobin -Enzymes: Proteins as reaction catalysts (cooperativity) -Enzyme kinetics -Enzyme regulation Today!
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Last lecture 3) All processes that we discussed as occurring in the capillaries are reversed in lungs: Lungs Needy tissue 1) Transported O 2 2) Many features of hemoglobin lower affinity of binding to O 2 (makes larger) O 2 bound, H+ released, carbamate released from amino-termini, HCO - converted to CO 2
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Earlier lecture: perhaps unclear Amphipathic α -helices and β -sheets β -sheet : two dimensional, neighboring peptide chains linked by backbone H-bonding vs. -sandwich ( silk and spider webs): three dimensional stacking of multiple -sheets Alternating hydrophobic and polar side chains: amphipathic sheets that can interact with other β -sheets In a “sandwich’ or
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Today: 1) Features of enzymes I have posted a practice exam and key on Blackboard I will hold a recitation in preparation for the exam on Tuesday, Feb. 7 here in Leidy 10, 7:00-8:00 PM 2) How do enzymes work: the transition state and some examples 3) Reaction coordinate diagrams and activation energy 4) Enzyme kinetics Note: you can supplement reading for this lecture by pp. 183-192, 194-205 In Lehninger, Principles of Biochemistry, 5th ed. a pdf will be posted on Bb!! -V max and K m -Michaelis/Menton equation -k cat and enzyme efficiency
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Enzymes Enzymes (literally, “in yeast”) are the chemical reaction catalysts of biological systems. Most enzymes are proteins, and they often use metal ions or prosthetic groups like vitamins to assist catalysis. Many inherited genetic disorders result from a defect or even a total absence of a particular enzyme, or excessive activity of an enzyme. Measurement of enzyme activities in body fluids is important in diagnosing various illnesses. Furthermore, many drugs act by altering the activities of enzymes. And enzymes are practical tools in the laboratory.
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Enzymes- biochemical reactions are caused by molecules
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Enzymes- discovery http://informedfarmers.com/crops/minor-pulses/
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Enzymes- discovery Figure 3-36 Molecular Biology of the Cell (© Garland Science 2008)
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Enzymes- features Chymotrypsin Figure 3-37a Molecular Biology of the Cell (© Garland Science 2008) Lehninger Figure 6-1 Active site Enzyme activity requires native structure of the protein
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10 Figure 3-53 Molecular Biology of the Cell (© Garland Science 2008) Proteins (enzymes) often use the help of additional non-peptide molecules (co-enzymes) in their functions
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Enzymes- cofactors Table 3-2 Molecular Biology of the Cell (© Garland Science 2008) Lehninger Table 6-1 Metals: Cofactors that are derived from vitamins:
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Enzyme classification (Many enzymes also have common names) Example: Adenylate kinase Lehninger, http://www.brenda-enzymes.org
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Table 3-1
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This note was uploaded on 03/07/2012 for the course BIOL 212 taught by Professor Kina during the Spring '12 term at UPenn.

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Slides 6 013112(1) - Lecture overview We are now discussing...

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