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Concepts in biochemistry Review session Nov. 26, 2007.

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Presentation on theme: "Concepts in biochemistry Review session Nov. 26, 2007."— Presentation transcript:

1 Concepts in biochemistry Review session Nov. 26, 2007

2 pH = -log [H+] concentration of hydrogen ions pKa = -log Ka susceptibility for hydrogen removal Ka is proton dissociation constant Ka = [H+] [A-]/ [HA] pH = pKa when acid HA is HALF neutralized and you have as much acid as ions

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4 Carbonic acid pKa = 3.5 (strong acid!) Carbonic anhydrase Zn-dependent, rate = 10 6 /s pH drops helps O 2 release

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6 often in cat. center, good H+ acceptor disulfide bonds pigments, thyroid hormones

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8 ? ?

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10 chemically what kind of bond?

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14 Interactions between side chains shape tertiary structure of proteins

15 Interactions between individual polypeptides shape quarternary structure Collagen

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18 Enzymes don’t change the equilibrium only the RATE of an reaction

19 Catalysis

20 Substrate concentration at Vmax/2 Km=dissociation/association

21 Lineweaver-Burk 1/Vo=Km/Vmax x 1/s + 1/Vmax

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23 High substrate concentrations can outcompete the inhibitor

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25 Unproductive reaction = at same amount of substrate, you lower Vmax,

26 Example: The antibiotic Deoxycyclin is a noncompetitive inhibitor of collagenase and is used to treat peridontal disease Unproductive reaction = at same amount of substrate, you dramatically lower Vmax, binds enzyme in absence and presence of substrate

27 IMPORTANT: Allosteric enzymes DO NOT obey MM kinetics, because they contain multiple subunits that affect each other (e.g., hemoglobin)

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30 Chymotrypsin: Ser part of catalytic triad

31 Catalytic triad: Asp positions His, His extracts hydrogen from Ser, Ser attacks carboxyl-terminal side of Trp, Tyr, Phe or Met (large hydrophobic residues) Chymotrypsin has highly reactive Ser residue

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34 Niacin = Vit B3

35 FMP AMP

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38 TPP = thiamine pyrophosphate

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41 Production of pyruvate

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44 Net gain in glycolysis: 2ATP 2 NADHs

45 Dead end

46 The Cori Cycle

47 stimulated by insulin

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49 Sources for glucose production underlined

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54 nucleotide metabolism (to make nucleotides, NOT to gain energy)

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61 Electron transport chain in the mitochondria

62 Increasing potential to accept electrons Complex I II III IV ubiquinone

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65 outside inside

66 You make 30 ATPs/1glucose

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68 Acyl carrier protein

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72 Diabetic ketosis in the absence of insulin


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