Biochem FINAL known topics Flashcards
Cytochrome C
Has Heme cofactor Involved in redox chemistry Soluble e- carrier Takes e- from C3 to C4 one at a time in IMS
Types of Enzyme inhibition?
Competitive Inhibitor Uncompetitive Inhibitor Mixed (noncompetitive inhibition) Inactivators
Inhibitor definition:
Substances that reduce an enzyme’s activity
Competitive inhibitor
- Most common
- Often resembles substrate
- Compete for substrate binding site
- Can be overcome by adding more substrate.
- I binds to E; results in k1 appearance decreasing.
Competitive Inhibitor: Km and Vmax
- Km = (K-1 + K2)/k1;
- km = increases
- Vmax = k2[ES] v
- max = unchanged
Uncompetitive Inhibition
- I binds to ES only;
- Blocks ES —> E+P K-1 and K2 both are effected,
- K-1 and k2 both decrease;
- which causes km to decrease
- Vmax also decreases
- Cannot be overcome by adding more substrate.
- K-1 and k2 both decrease;
- K1 unaffected.
Mixed (noncompetitive) Inhibition
- I affects both substrate binding and catalysis.
- I binds to ES + E
- k1, k-1, k2 all decrease
- Km can either increase or decrease
- Vmax decreases
- Plot crosses to the left of the y-axis.
Pure noncompetitive inhibition:
- I binds with same affinity to both E + ES
- Km app = Km (no change)
- All lines cross over at some point at the x-axis,
- vmax still causes the y-intercept to be different.
Inactivators
Permanently inhibit enzymes Could add new functional group to binding site on an enzyme Affects vmax but not km (mimics non-competitive inhibition)
Sulfanilamide
- Competitive Inhibitor
- Inhibits PABA synthesis,
- which disables folate synthesis.
- Doesn’t affect humans since we get folate from our diet.
PABA is a precursor for?
Folate
What is folate used for?
Needed for DNA synthesis.
2 Stages of Glycolysis
- Energy Investment (1-5)
- Energy Recovery (6-10)
1st stage of Glycolysis:
- Energy Investment
- Rxns 1-5
- Consume
- 2 ATPs/Glc
- Yield
- 2 glyceraldehyde-3-P (GAP)
2nd stage of Glycolysis:
- Energy Recovery “payoff”
- Rxns 6-10
- Yields:
- 2 ATP per GAP
- 1 Pyruvate per GAP
- 1 NADH per GAP
Competitive Inhibitor Lineweaver-Burk plot
Uncompetitive Inhibitor Lineweaver-Burk plot
Noncompetitive Inhibitor Lineweaver-Burk plot
Ezyme Catalysis
- Enzymes are proteins
- Actvie site
- Specificity (lock and key)
- Complementary: (stereo) (CAnt have mirror image)
- Geometric specificity
- Electronic
- Complementary: (stereo) (CAnt have mirror image)
- Specificity (lock and key)
- Actvie site
Structure of ATP
Hexokinase
- First reaction of Glycolysis
- Kinase transfers phosphory group from ATP to Glucose C6
- Mg2+ shields charges
- Glucose induces conformational change.
Delta G = 0
Equilibrium
Delta G > 0
Non-spontaneous; Endergonic
Delta G < 0
Spontaneous; Exergonic
Defining structures of primary structure?
A.a. sequence and disulfide bonds.
Defining structures of secondary structure?
- Spatial arrangement of back bone with minor considerations of side chains.
- a helix
- B sheets
Defining structures of tertiary structure?
Spatial arrangement considering side chains;
- determines where hydrophobic and hydrophilic subunits are.
Defining structures of quartenary structure?
Includes subunits of proteins that multiple.
Classes of enzymes
Glycolysis Net Production
- For every glucose
- 2 ATP
- 2 NADH
- 2e- each
Where does glycolysis take place?
Cytosol
Where does ETC take place?
Mitochondria
