GSK1379725A is a selective BPTF ligand (Kd: 2.8 uM). It also shows no binding activity for Brd4.

GSK1379725A has proven to be selective towards Brd4, though comprehensive evaluation against other bromodomains is necessary. Searches in the ChEMBL database reveal its activity in only five cellular assays, indicating a potency (EC50) of 500 nM, with no kinase activity noted despite extensive screenings, especially with the PKIS library[1]. NMR titration data showed a separation of 171 Hz between bound and unbound resonances of GSK1379725A, suggesting a maximum chemical exchange rate. Based on an assumed high association rate (e.g., similar to chymotrypsin: proflavin at 1.2×108 M-1 s-1), the dissociation constant (Kd) is approximately 8 μM. For more precise Kd measurement, ITC was employed with unlabeled BPTF, yielding a Kd of 2.8 μM, aligning with the observed intermediate exchange resonance broadening detected by PrOF NMR, thus confirming the specificity and binding characteristics of GSK1379725A.