A breakdown product of JAK3 Inhibitor-IV (Cat. No. 420121) with similar inhibitory potency (pIC50 = 6.8 for JAK3; 5.0 for EGF-R; 4.7 for JAK1). Also inhibits STAT-5 phosphorylation and T-cell proliferation.http://www.creative-enzymes.com/product/JAK3-Inhibitor-V_3023.html