Calculate the molar concentration of substrate

AI Thread Summary
To calculate the molar concentration of the substrate for a Michaelis-Menten curve, the volume of substrate added to each well is multiplied by its concentration to obtain the mass. The formula weight of paranitrophenylphosphate is 275 g/mole, and it is diluted in 100 µL in each well. An example calculation shows that for 10 µL of substrate, the resulting concentration is approximately 3.580e-4 M after converting units and calculating moles. The discussion emphasizes the correct approach of converting volume to mass, mass to moles, and then moles to concentration. The calculations appear to be on the right track, though some participants express confusion about the process.
Thrax
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Homework Statement


Hello,
I'm creating a Michealis/Menten curve and need to find the X values for the graph.


Homework Equations



These are the instructions given to find the X values:

To obtain the X value, plot the molar concentration (molarity) of substrate used in each well.

You can determine this by multiplying the volume of substrate added to each well by the concentration of the substrate (1 mg/ml or 1 ug/ul) to give you a mass.


Paranitrophenylphosphate (the substrate) has a formula weight of 275 g/mole.

The substrate is diluted in 100uL in each well.

Using these values, calculate the molar concentration of substrate in each well across the plate. These are the X values. You are now ready to plot the kinetics curve.

The Attempt at a Solution



Using one data set of for 10uL of substrate i calculated moles
First converted the 10uL to .010mL

.010mL * 1 mg/ml = .010mg mass of substrate

Converted the .010mg to grams and solved for moles

1.000 x10-5g (1mol / 279g) = 3.58 x10e-8 moles

converted the 100ul to liters

100e-6uL = 1.000e-4 L


then found found moles\liters

3.58 x10e-8 moles / 1.000e-4 L = 3.580e-4 M

Not sure if this is correct or not. I also tried taking the 10ug / 100ul = .100 ug/uL and doing something with that, but got totally lost...
 
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I have just skimmed not checking numbers, but it looks to me like you are following the right path - volume to mass, mass to moles, moles to concentration.


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Thanks for taking a look!
 
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