Hi there,

Recently I'm doing with protein extraction and further enzyme activity assay, i.e. nitrate reductase activity in A.thaliana and B.napus. Many recipes regarding extraction buffer preparation do mention that, both EDTA and Mg ions are both added, which is for chelating disturbing metal ions and serving as ligands to stalize proteins in extration process, respectively. But I'm really doubting, occurrence of BOTH MATERIALS would make neither really work, since EDTA could chelate the Mg ions theoretically. So what's the purpose of this move? or there might be certain exception that the Mg ions would not chelated by EDTA and therefore both can coordinate pretty well during extraction?

Many thanks in advance.