I have synthesized several compounds that only dissolved in DMSO. The problem arose when I'm doing an enzyme inhibition assay. The compound should dissolved in 5-10% DMSO, otherwise the assay cannot be done. Is it possible if i use 100% DMSO to make a stock solution of my compound and corrected the result using 100% DMSO as negative control ?
Yes, you just need proper controls. Enzymes will have different tolerances for DMSO, and so the first step will be to measure your enzyme rate at different DMSO concentrations. Once you know the maximum DMSO tolerated without loss of activity/denaturing, you can design your inhibition assay. If your enzyme loses a lot of activity or denatures at these DMSO concentrations, you might have to try other solvents until you find something compatible.
For example, I worked with an enzyme that retained 100% activity up to 7% v/v DMSO and then started precipitating near 10% v/v. I then wanted to test an inhibitor from 1 mM to 1 µM so I prepared 20X stocks of each inhibitor concentration (20 mM to 20 µM) in 100% DMSO. From these stocks I added the inhibitor to the enzyme to a final concentration of 5% v/v, or 1:20 dilution and the inhibitor did not precipitate. The positive control receives just 5% v/v DMSO with no inhibitor. Using this design you can confidently measure the effect of the inhibitor while controlling for the effect of DMSO consistently across replicates.
Hope this helps!
ACA
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