Purity > 90% as determined by SDS-PAGE. MW: 74kDa. Full Length of Mature Protein: 2-513aa. N-terminal 6xHis-SUMO-tagged. Escherichia coli (strain K12). Degradation of inorganic polyphosphates. Orthophosphate is released progressively from the ends of polyphosphate of circa 500 residues long, while chains of circa 15 residues compete poorly with polyphosphate as substrate.