2.3.1.192 Ca2+ activation at both physiological and high substrate concentration 487438 2.3.1.192 K2SO4 55 mM, 67% residual activity at physiological substrate concentration, 110% of initial activity at high substrate concentration 487438 2.3.1.192 Mg2+ 1 mM, about 10% activation, 10 mM, inihibition at physiological substrate concentration, activation at high substrate concentration 487438 2.3.1.192 additional information addition of monovalent cations is required 486265