I am doing an alpha-amylase assay and I am getting negative numbers for the inhibition as my sample concentration increases. I am using:
CNPG3 as substrate and trisodium phosphate pH 11 as stop solution of reaction.
Also, I have adjusted the control without inhibitor with 2.0 % DMSO, because my samples have this same solvent concentration.
I have got a great inhibition curve for acarbose.