Identification of the bovine brain Ins(1,4,5)P3 5-phosphatase after SDS-polyacrylamide gel electrophoresis.

Ins(1,4,5)P3 5-phosphatase catalyzes the dephosphorylation of Ins(1,4,5)P3 in the 5-position. In a high speed soluble fraction of bovine brain, there are two soluble 5-phosphatases: type I and type II. The purified Ins(1,4,5)P3 5-phosphatase type I exhibits a major silver-stained band of 43 kDa on denaturing (SDS) gels. It is possible to extract the 5-phosphatase activity form a duplicate lane after gel electrophoresis. The 43 kDa region contains the extractable Ins(1,4,5)P3 5-phosphatase activity.