This enzyme also phosphorylates Ins(1,4,5)P3?to Ins(1,3,4,5)P4, Ins(1,3,4,5)P4?to Ins(1,3,4,5,6)P5, and Ins(1,3,4,5,6)P4?to Ins(PP)P4, isomer unknown. The enzyme from the plant?Arabidopsis thaliana?can also phosphorylate Ins(1,3,4,6)P4?and Ins(1,2,3,4,6)P5?at the?D-5-position to produce 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate (InsP6), respectively [3]. Yeast produces InsP6?from Ins(1,4,5)P3?by the actions of this enzyme and EC?2.7.1.158, inositol-pentakisphosphate 2-kinase [4].