Fig. 2

Establishment of the continuous coupled assay for MTs using short peptide as a substrate a. The detection of MTs activity is dependent on all assay components. The reaction cannot be monitored in the absence of SAM (orange), SAHN (grey), ADE or glutamate dehydrogenase (Additional file 1: Figure S1). In addition, very low activity was monitored in the presence of SET7/9 inactive mutant (yellow). Activity is measured only when all reaction components are present including the peptide substrate (TAT peptide as an example, blue). b SET7/9 activity is the rate-limiting step in the three enzyme coupled assay. Each enzyme was monitored separately to ensure the determination of SET7/9 activity. Absorbance values at 340 nm in all reactions are normalized to 1 and the change in absorbance over time is presented as 1—the absorbance value obtains for each measurement. For represented raw data of absorbance change at 340 nm please see Additional file 1: Figure S4. c SET7/9 activity with TAT peptide (500 μM) at increasing enzyme concentrations including 1, 3, 6 μM leads to a proportional increase in reaction rate highlighting that this is the rate-determining step for the coupled assay