Inositol hexakisphosphate kinase 1 (IP6K1) and 3 (IP6K3) phosphorylate inositol 1,2,3,4,5,6-hexakisphosphate (IP6) to inositol 5-diphospho-1,2,3,4,6-pentakisphosphate (5-PP-IP5).
The following lists the above proteins with their corresponding literature references: IP6K1 (Saiardi et al. 2001, Mulugu et al. 2007, Draskovic et al. 2008; Lin et al. 2009) and IP6K3 (Saiardi et al. 2001, Draskovic et al. 2008).