GCN2-IN-1 (A-92) is a potent general control nonderepressible 2 kinase (GCN2) inhibitor with an IC50 of <0.3 μM in the enzyme assay and an IC50 of 0.3-3 μM in the cell assay.
GSK4028 is the enantiomeric negative control of GSK4027, which is a PCAF/GCN5 bromodomain chemical probe, the pIC50 of GSK4028 is 4.9 in a time-resolved fluorescence resonance energy transfer (TR-FRET) assay.