2.1.1.274 K+ 2fold increase in activity in the presence of 5 mM K+ 726129 2.1.1.274 K+ 5 mM, stimulates SAMT activity by a factor of 2 721412 2.1.1.274 KCl activates at 1 mM 756767 2.1.1.274 additional information Na+, NH4+ and Mg2+ have no effect on isoform SAMT1 activity 726129