Figure 6.

LSD1 inhibitor efficiency can be measured quantitatively using MassSQUIRM. (A) Demethylation reactions were carried out using 125 ng of LSD1 and 0.25 µg H3K4me2 peptide in the presence (top part) or absence (middle part) of 16.7 mM of the LSD1 inhibitor phenylethylhydrazine. (B) Quantification of methylation levels was determined using r₁ and r₂ values from peptide alone samples (A, bottom part) and equations 5–7. Open circles indicate light methylation while closed circles indicate heavy methylation.