k ( d ) measurements over a range of cation concentrations revealed that a half-maximal restoration of binding affinity was obtained with relatively low levels ( 10 to 50 mum ) of divalent cations ( e.g. , ca ( 2+ ) , mg ( 2+ ) , and ethylenediammonium ( 2+ ) ions ) .
C0007447
cation
C0007448
divalent cations