Mcim 326 L9 regulatory mechanisms (inc)

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Scottygo
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Mcim 326 L9 regulatory mechanisms (inc)
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2013-10-16 00:28:25
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Mcim 326 L9 regulatory mechanisms
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Mcim 326 L9 regulatory mechanisms
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  1. Equilibrium Constant
    Keq=
  2. Free Energy
    • R=constant
    • T=Absolute Temperature
  3. The 5 Regulatory mechanisms (speac)
    -which regulate enzyme activity and which regulate enzyme concentration
    Activity:

    • Substrate level
    • Allosteric
    • Covalent modification
    • Protein interactions

    Concentration:

    Enzyme levels
  4. SUBSTRATE LEVELS
    How can substrate levels be used for regulation?
    3 ways
    • -IN A METABOLIC PATHWAY CHANGES IN SUBSTRATE CONCENTRATION [A] AFFECT THE PATHWAY AND CAN BE VERY RAPID(MICROSECONDS).
    • A-->B-->C-->D

    1) SUBSTRATE CAN BE DIVERTED INTO ANOTHER PATHWAY A --> E

    2)TRANSPORT OF A INTO OR OUT OF THE CELL CHANGES [A].

    3)OTHER REACTIONS CAN PRODUCE SUBSTRATE A: F --> A  G -->A
  5. MICHAELIS-MENTION PLOT
    What is the underlying concept?
    • [S] AFFECTS REACTION RATES
    • as concentration increases so do reaction rates (V:velocity)
  6. V VS. [S] graph is what shape?
    A HYPERBOLA
  7. What is KM
    • -MICHAELIS MENTON CONSTANT
    • -USUALLY A MEASURE OF TIGHTNESS OF BINDING OFS TO THE ENZYME.
  8. KM (LOW) =
    HIGH ACTIVITY AT LOW [S] AND VISA VERSA
  9. When is Km = [S]?
    At vmax/2
  10. Examples of allosteric regulation
    THREONINE DEAMINASE
    how is KM effected?
    • -first reaction in isoleucine pathway
    • -irreversible
    • - allosterically inhibited by isoleucine which is and end product of the pathway

    -Isoluecine increases Km of enzyme for Threonine (the substrate)
  11. Example of Allosteric Regulation
    Aspartate Transcarbamoylase (ATCase)
    • -FIRST REACTION IN THE PYRIMIDINE NUCLEIC ACIDPATHWAY
    • -BOTH END PRODUCTS ARE INHIBITORS. WHY?-ATP ACTIVATES:WHY?
  12. T (TAUT) STATE OF ENZYME
    WITHOUT SUBSTRATES OR ACTIVATOR
  13. R (RELAXED) STATE OF ENZYME
    WITH SUBSTRATES AND/OR WITH ACTIVATOR – PROTEIN HAS CHANGED SHAPE. BINDS SUBSTRATE MORE EASILY
  14. Example of Covalent Modification
    GLUTAMINE SYNTHETASE
    -GLUTAMINE SYNTHETASE (GS) IS REGULATED BY COVALENT ATTACHMENT OF AMP(ADENYLYLATION) IN E. COLI.
  15. GS-AMP IS ___ ACTIVE
    LESS
  16. WHAT DOES COVALENT MODIFICATION ALLOW?
    LARGER, MOREPERMANENT REGULATORYEFFECTS TO OCCUR.
  17. WHAT IS THE ENZYME WHICH ADENYLYLATES GS?
    AT-ase
  18. Example of regulation by  Protein interactions
    ADENYLYL TRANSFERASE (ATase)
    function
    what protein interacts?
    THE ENZYME WHICH ADENYLYLATES GS, IS REGULATED BY BINDING OF A PROTEIN CALLED PII

    PII is permanently bound and is regulated by covalent modification
  19. PII IS COVALENTLY REGULATED BY ____
    • URIDYLYLATION
    • (ATTACHMENT OF UMP).
  20. PIIA CAUSES ATase TO :
    • ADENYLYLATE GS
    • -A FOR ADENYLYLATING
  21. PIID-UMP CAUSES ATase TO
    DEADENYLYLATE GS
  22. UMP is added to PII by:
    UTase (URIDYLYLTRANSFERASE)
  23. Histidine Protein kinase is an example of what type of modification?
    what system is it from?
    • phosphorylization
    • PTS transport system
  24. ATCase CATALYTIC PROTEIN SUBUNITS(S)
    regulated by what?
    example of what type of regulation?
    effectors?
    REGULATED BY REGULATORY SUBUNITS(R)

    protein interaction

    ATP, CTP, UTP -> bind to R subunit which regulates S subunit
  25. Protein interactions can involve what three of the other mechanisms?
    • Allosteric regulation
    • covalent modification
    • Enzyme levels
  26. The 5 Regulatory mechanism differ in what 3 important ways?
    How do the 3 correlate to each other?
    • Size
    • Speed
    • Permanence

    As size and permanence increase speed drops
  27. order the 5 Regulatory mechanism according to speed
    substrate>Allosteric>Covalent>Protein>Enzyme

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