Biochem Chap 12

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Biochem Chap 12
2011-03-22 23:02:16
rate equation

chapter 12 biochemistry
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  1. rate equation
    a mathematical expression for the time-dependent profress of a reaction as a funtion of reactant concentration
  2. rate constant (k)
    The proprtionality constant between the velocity of a cemical reaction and the concentration(s) of the reactant(s)
  3. ES complex
    The enzyme-substrate complex, whose formation is a key component of the Michaelis-Menten model of enzyme action. Also known as the Mechaelis complex
  4. k1
  5. k2
    the rate constant for the second step of a simple enzyme-catalyzed reaction that follows Michaelis-Menten kinetics that is the conversion of the ES complex to E + P
  6. k-1
    the rate constant for the reverse reaction e.g. breakdown of the ES complex to E+S
  7. steady state
    a set of conditions in an open system under which the formation and degradation of individual components are balanced such that the system does not change over time
  8. steady state assumption
    a condition for the application of the Michaelis-Menten model to an enzymatic reaction, in which the concentration of the ES complex remains unchanged over the course of the reaction
  9. KM
    for an enzyme that follows the Michaelis-Menten model, KM= (k-1+ k2)/k1 , KM is equal to the substrate concentration at which the reaction velocity is half-maximal
  10. Michaelis-Menten equation
    mathmatical expression that desribes the activity of an enzyme in terms of the substrate concentration [S], the enzyme maximal velocity (Vmax) and its Michaelis constant KM: v0= Vmax[S]/ (KM+ [S])
  11. v0
    initial velocity of an enzymatic reaction
  12. Vmax
    maximal velocity of an enzymatic reaction
  13. enzyme saturation
    a state in which the substrate concentration is so high that essentially all the enzyme molecules are in the ES form.
  14. kcat (turnover number)
    the catalytic constant for an enzymatic reaction, equivalent to the ratio of the macimal velocity (Vmax) and the enzyme concentration ([E]T)
  15. kcat/KM
    the apparent second-order rate constant for an enzyme-catalyzed reaction; it is a measure of an ezyme's catalytic efficiency
  16. diffusion controlled limit
    the theoretical maximum rate of an enzymatic reaction in solution, about 108 to 109 M-1s-1
  17. Which rate constant describes the conversion of substrate to product in Michaelis-Menten kinetics?
    • a. k1
    • b. None of these
    • c. k-1
    • d. k2