The production of D∗± mesons in deep inelastic ep scattering has been measured for exchanged photon virtualities 5 < Q2<1000GeV2, using an integrated luminosity of 363 pb−1 with the ZEUS detector at HERA. Differential cross sectionshave been measured and compared to next-to-leading-order QC D calculations. The cross-sections are used to extract the charm contribution to the protonstructure functions, expressed in terms of the reduced charm cro ss section, σc̄cred. Theoretical calculations based on fits to inclusive HERA data are compared to the results.