Uses inorganic polyphosphate (polyP) as a donor to convert NDP to NTP. PolyP hydrolysis is slightly faster with GDP, but it can also use ADP, CDP and UDP. [phosphate](n) + ATP = [phosphate](n+1) + ADP [phosphate](n) + CTP = [phosphate](n+1) + CDP [phosphate](n) + GTP = [phosphate](n+1) + GDP [phosphate](n) + UTP = [phosphate](n+1) + UDP Shows little dependence on metals. kcat is 251 min(-1) with GDP as substrate. Has two pH optima at 8 and 10. Belongs to the polyphosphate kinase 2 (PPK2) family. Class I subfamily.