Bmsc 200 Mech of Enzymes

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  1. Co-factors
    • -requirement of some enzymes for full activity
    • -inorganic ions (Mg2+, Fe2+, etc.)
  2. Co-Enzymes
    • -requirement of some enzymes for full activity
    • -organic molecules (Vitamins)
  3. prosthetic group
    A co-enzyme or co-factor that is tightly associated(permanently) with the enzyme
  4. Holoenzyme
    Apoenzyme + Required Co-factor/Co-enzyme
  5. Apoenzyme
    The protein component of an enzyme, to which the coenzyme attaches to form an active enzyme.
  6. Oxidoreductases
    Transfer of electrons (hydride ions or H atoms)
  7. Transferases
    Functional Group transfer reaction
  8. Hydrolases
    hydrolosis reaction (transfer of functional group to water)
  9. Lyases
    addition of groups to double bonds, or formation of double bonds by removal of groups.
  10. Isomerases
    transfer of groups within molecues to yield isometric forms
  11. Ligases
    formation of c-c, c-s, c-o and c-n (covalent) bonds by condensation reactions coupled to ATP cleavage
  12. Catalysts: 3 features
    • -lower the amount of energy required for a reaction to proceed
    • -speed up attainment of equilibrium but do not change equilibrium
    • -are unchanged by the reaction; recycled to participate in another reaction
  13. Enzymes vs Chemical Catalysts  
    4 points
    • 1) Faster
    • 2) Milder conditions
    • 3) Greater specificity
    • 4) Potential to be regulated
  14. Substrate (S):
     the molecule to be actedupon by the enzyme
  15. equation for velocity
    V= k[S]

    • k- rate constant
    • [S]- concentration of substrate
  16. What is the relationship between the rate constant and the free energy of the transition state
    inverse and exponential
  17. What is the main physical limitation on reaction speed of an enzyme
    Rate of difusion
  18. The two Binding Effects an enzyme can have on a substrate
    • 1) Substrate Binding (proximity effect)
    • 2) Transition-state Stabilization
  19. Proximity Effect of Enzyme:
    5 steps
    • (1)  Reduces the entropy (decreased freedom of motion of two molecules in solution). 
    • (2) Desolvation of the substrate to expose reactive groups 
    • (3) Alignment of reactive functional groups of the enzyme with the substrate 
    • (4) Distortion of substrates 
    • (5) Induced fit of the enzyme in response to substrate binding
  20. Transition-state analogs
    stablecompounds whose structures resemble unstable transition states. Used as a enzyme inhibitor. (active site blocker)
  21. Catalytic antibodies
    antibodies evoked by man made antigens (Transition state analogs) that have specific catalytic capabilities towards a targeted molecule.(TS analog will mock the targeted molecules TS state)
  22. the two types of chemical catalysis by enzymes
    • 1)Acid/base Catalysis
    • 2)Covalent Catalysis
  23. what are the two main feature of Acid base Catalysis
    • -Reaction acceleration is achieved by catalytic transfer of a proton to or from side chain Aminos of enzyme (histidine is important in this way)
    • -at end of reaction the amino must be returned to original protonated state
  24. In covalent catalysis how is group X transfered from subrate A to substrate B?
    A-X  +  Enz Image Upload X-Enz  +  A

    X-Enz  +  B  Image Upload B-X  +  Enz
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Bmsc 200 Mech of Enzymes
2012-11-26 21:57:14
Bmsc 200 Mech Enzymes

Bmsc 200 Mech of Enzymes
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