SB203580 (HCl), 5 mg

STEMCELL Technologies supplies this small molecule for stem cell research applications. It is a potent inhibitor of p38 mitogen-activated protein kinase (MAPK) activity (IC50 = 0.6 µM), acting on both the α and β isoforms of p38 MAPK, and does not inhibit ERK or JNK.

The compound is provided as a hydrochloride salt of the molecule, which has greater solubility than the free base form. Alternative names are PB 203580 and RWJ 64809. The CAS number is 869185-85-3, the molecular weight is 413.9 g/mol, and the purity is ≥ 95%. It is supplied as a crystalline solid that is stable at -20°C as supplied for 12 months from date of receipt. Solubility is ≤ 70 mM in DMSO and ≤ 70 mM in absolute ethanol. Stock solutions should be prepared fresh before use, and the compound has low solubility in aqueous media.

Published applications include maintenance and self-renewal: enhancing growth and self-renewal of mouse embryonic stem cells, promoting long-term maintenance of human naïve pluripotent stem cells, promoting proliferation of human endothelial progenitor cells, and promoting proliferation of neonatal and adult rat cardiomyocytes. In differentiation studies, it enhances differentiation of cardiomyocytes from human ES cells, and inhibits differentiation of cardiomyocytes from mouse ES cells by inhibition of early mesoderm.