Metal content - (Apr/04/2008 )

Hi everyone,
i just try to substitute different hetero metals for iron in my protein by refolding inclusion bodies in presence of the appropriate metal, e.g. cobalt, manganese, nickel.
I observe a good incorporation of cobalt, but a very low incorporation of the other hetero metals. Does anyone know, what kind of factors can decrease the metal incorporation?
Thanks in advance

valence. coordination number.

jepp, already checked for it. the metals i used have a quite similar ion radius and they almost got all the same amount of valence electrons

cobalt and iron can also be hexavalent.