What equation should I use to find the enzyme and substrate concentrations that

Question

What equation should I use to find the enzyme and substrate concentrations that correspond with this graph of absorbance over time? Thank you for your time.

[Enzyme] [Substrate] 1.5 1.5 1 d 4.17nM d 4.17nM 10 mM 12 mM 0.5 b 0.08 b 4.17nM o.04mM 0.02mM 0.04 a 4.17nM 30 0 time, sed Lines a-e in the figure above show the change in absorbance as an enzyme catalyzes conversion of substrate to product that absorbs at 254nm under the same set of buffer, pH and temperature (298K) conditions. Enzyme and substrate concentrations are given for reactions corresponding to lines a and b, and d (two different combinations of enzyme & substrate concentrations give the results shown for line d). A change in absorbance of 1.98 OD254 corresponds to 1 mM product formation. Assume that the enzyme obeys Michaelis-Menten kinetics 1. Suggest a combination of values for [Enzymel and [Substrate] that would give rise to the results observed for a. line d b. line e For both (a) and (b), explain your reasoning and/or show your calculations. 2. Estimate by how much the enzyme stabilizes the transition state at 25°C in kJ/mol if the uncatalyzed rate constant is 0.8 s1

Explanation / Answer

You should know the initial velocity which is equivalent to the rate of product formation,
also from the graph it is clear that rate of product formation increases with time which
as time progresses this process will slow down.
Now if you observe how the velocity changes with various substrate concentrations and plot
on the graph as velocity vs substrate concentration you would end up getting Michaelis menten
equation,
v = Vmax [S] / Km + [S]
and using the below equation you would get enzyme concentration.
Vmax = Kcat [E]

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