Description
R112 is an inhibitor of spleen tyrosine kinase (Syk; IC
50 = 226 nM in cultured human mast cells) that acts in an ATP-competitive and reversible manner (K
i = 96 nM). It inhibits mast cell and basophil degranulation induced by anti-IgE cross-linking (EC
50s = 353 and 280 nM, respectively). It also inhibits basophil degranulation induced by an allergen with an EC
50 value of 490 nM. R112 inhibits the production of leukotriene C
4 (LTC
4; ) and decreases cytokine levels in cultured human mast cells.