# Chapter 7.4 Enzyme Kinetics Flashcards

what does kinetics generally relate to?

movement

what is enzyme kinetics?

study of rates of enzymatic reactions

what do enzyme kinetics relate?

relate rates to activation energy (delta G double dagger) and equilibrium

what do enzymes do for reactions? how?

increase the rate that a reaction reaches equilibrium by lowering activation energy

do enzymes change overall reaction energy (delta G)?

nope! they can’t change equilibrium

what are the 2 ways to describe rate?

- apprearance of products over time (dP)
- disappearance of reactants/substrate over time (dS)

what are the units and standard units of rate?

concentration over time, or Molarity/second

what is the general reaction rate law?

v= k[S]^n

what is k in the general reaction rate law?

the rate constant

does k, the rate constant, depend on concentration?

no

can k, the rate constant, be altered by catalysts or temperature?

yes

how is k, the rate constant, determined?

experimentally

what is n in the general reaction rate law?

the order of the reactant, or the effect of substrate concentration on rate

what does the overall order of a reaction tell you? how is it found?

tells how the concentration of all reactants affects the rate of the reaction; is the sum of the exponents in the rate law

what does the order with respect to a reactant tell you? how is it found?

tells how the concentration of a single reactant affects the rate of the reaction; is the exponent on a specific reactant in the rate law

what is the equation to find the units of k, the rate constant?

k units = M^1-n x t^-1

how is rate related to activation energy?

there is an inverse relationship between rate (v) and activation energy (delta G double dagger), so the lower the activation energy, the faster the rate of the reaction and vice versa

what do enzyme kinetics depend on? what is the issue with this?

[S], substrate concentration is difficult to measure

what do we measure instead of [S] for enzyme kinetics?

[P], concentration of products

how can rate also be determined? (a formula)

dP/dT

how to we determine initial rate? (Vo)

Vo = dP/dT

what does initial rate (Vo) increase with?

increasing initial [S]

what does each axis represent in the michaelis-menten plot?

X axis is inital [S]

Y axis is initial velocity [Vo]

what is the slope of each line on the michaelis menten plot?

Vo

what is Vmax? where is it found on a michaelis menten plot?

the max velocity of a reaction, the top of the curve on a Michaelis-menten plot

why does Vmax exist for enzymatic reactions?

because you only have so many enzymes, so once they are all bound to subrates, you can’t make more product even if you have more substrates