Multiple Inositol Polyphosphate Phosphatase 1 (MINPP1)

MINPP1 encodes multiple inositol polyphosphate phosphatase; an enzyme that removes 3-phosphate from inositol phosphate substrates. It is the only enzyme known to hydrolzye inositol pentakisphosphate and inositol hexakisphosphate. This enzyme also converts 2,3 bisphosphoglycerate (2,3-BPG) to 2-phosphoglycerate; an activity formerly thought to be exclusive to 2,3-BPG synthase/2-phosphatase (BPGM) in the Rapoport-Luebering shunt of the glycolytic pathway.Sequence analysis predicted that the 487-amino acid MINPP1 protein is 84% identical to rat Mipp and about 53% identical to chick HiPER1. The N terminus of MINPP1 contains an ER-targeting domain consisting of a relatively long net-positive-charge (n) region, a hydrophobic core region, and a recognition site for signal peptidases.