BIIB 021(ab273599)

MW 318.76 Da, Purity >98%. Selective, Hsp90 competitive inhibitor (Ki = 1.7 nM). Displays no significant activity at a range of ATP-binding kinases or Na+K+ ATPase. Induces degradation of HER-2 in vitro (EC50 = 38 nM in MCF-7 cells). Inhibits growth and promotes cell death in a variety of human tumor cells. Orally bioavailable.