My stock protein concentration is 2.13mg/ml. I have to have a final concentration of 0.83 nanomoles and my final volume for the protein would be 50 microlitres. The molecular weight of the protein is 55kDa. I did a few calculations based on this and I got a volume of protein to add to my experiment, but it is impossible to measure it using pipettes. Do I have to dilute the protein more to get to a measurable volume for my final concentration?
The stock concenttation is 38.7 µM.
If you start with a 1:100 dilution of the stock, it will be 387 nM.
If you want 0.83 nM (not nanomoles) you could make a second 1:100 dilution to get to 3.87 nM.
Then, for 50 µl, you would need 10.72 µl of the 1:10,000 dilution.
Prepare the dilutions in the reaction buffer just before doing the reaction. The dilute enzyme solutions should not be saved.
With a suitable pipettor, you can start with only 1 µl of the original stock solution. If you don't have one of those low-volume pipettors and the tips that it requires, you can use 2 µl, which is the smallest usable volume for the commonly available 2-20 µl Rainin pipettor.
Haimantika Dey just be sure that as Adam B Shapiro pointed out you are needing 0.83nM (and not 0.83 nanomoles in 50ul volume.
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