FIGURE 7.

Kinetics of H540A hZIP4 zinc transport. The transport parameters, K_m and V_max, of the H540A hZIP4 mutant were elucidated at low (A) and high (B) concentrations of zinc by measuring the amount of ⁶⁵Zn²⁺ uptake into oocytes injected with hZIP4-Strep (with H540A mutant) mRNA over 1 h in assay buffer, which contained varying amounts of ⁶⁵ZnCl₂. The data were fit to the Michaelis-Menten equation described under “Materials and Methods.” Data originated from 4–7 oocytes; values are means ± S.E.