[ash]

i just can't seem to work out what the molar enzyme concentration is i need to calculate Kcat.
the enzyme was ADH with concentration of 0.1mg protein/ ml,
0.1ml was added to make up a total volume of 3ml.

from what i understand Kcat = Vmax/E  and E is the molar enzyme concentration, but i just keep going around in circles trying to work this out???

[ash]

i just can't seem to work out what the molar enzyme concentration is i need to calculate Kcat.
the enzyme was ADH with concentration of 0.1mg protein/ ml,
0.1ml was added to make up a total volume of 3ml.

from what i understand Kcat = Vmax/E  and E is the molar enzyme concentration, but i just keep going around in circles trying to work this out???

if somebody could just tell me how i calculate what E is?

[Dan]

1. The stock solution has a concentration of 0.1 mg/mL, convert this to mol/L. You will have to use the molar mass of ADH, which you have not given.

2. Now that you know the molar concentration of the stock solution, you can calculate the number of moles. You need to find the volume of stock solution used, and then calculate the moles of ADH in that volume from the concentration you got in part 1.

3. Now you know the moles, use the final volume to calculate the molar concentration of the new solution.

[ash]

i have unfortunately not been givn the molar mass biut from searches i believe it is 150.

so do i simply multiply this by my stock concentration (0.1mg protien/ml) to get the mol?

[ash]

1. The stock solution has a concentration of 0.1 mg/mL, convert this to mol/L. You will have to use the molar mass of ADH, which you have not given.

2. Now that you know the molar concentration of the stock solution, you can calculate the number of moles. You need to find the volume of stock solution used, and then calculate the moles of ADH in that volume from the concentration you got in part 1.

3. Now you know the moles, use the final volume to calculate the molar concentration of the new solution.

also my value for Vmax from my lineweaver burk plot is an inverse value how do i make this into a normal value?

[Dan]

i have unfortunately not been givn the molar mass biut from searches i believe it is 150.

If ADH is alcohol dehydrogenase (or any protein), then it is much more than 150 g/mol. Supposedly around 80000 g/mol for alcohol dehydrogenase.

Review what you know about converting mass to moles etc.

Molar mass (g/mol) = Mass (g) / moles (mol)

Molar concentration (mol/L) = moles (mol) / volume (L)

Mass concentration (g/L) = mass (g) / volume (L)

...and it follows that:

Molar concentration (mol/L) = Mass concentration (g/L) / molar mass (g/mol)