I am studying MAT activity in liver. Inicially,  I have used these incubation conditions: MAT (extract of liver 250 µg of protein) was assayed in a total volume of 250 µL of 100 mM Tris-HCl (pH 8.7), 150 mM KCl, 5 mM MgCl2, 5 mM ATP, 5 mM L-methionine,  5 mM dithiothreitol, proteosa inhibitor mix (1:1000),These conditions worked properly.

Now, after incubation the samples, I need to carry out an SPE method to clean-up the sample before running the sample in the Mass Spectrometer. My problem is that the buffer Tris-HCl is not compatible with my SPE cartridges, therefore I should  change the buffer. Could I use HEPES? Does HEPES work with MTA? Will I get the same enzymatic activity? I don´t know why people use always Tris-HCl, maybe it is essential.

Thanks in advance