3.6.1.25 K52R the His-tagged mutant loses 90-99% of its activity (catalytic efficiency is at least 1000times lower) compared to the wild type enzyme. Mn2+ does not induce a significant activation of this mutant 719965 3.6.1.25 K85A the His-tagged mutant is about 10times less active than the wild type enzyme, but the optimal conditions for activity are essentially the same. The mutant is more strongly activated by Mn2+ than by Mg2+, and the inhibitory effects of Ca2+ and Zn2+ are less pronounced 719965 3.6.1.25 K8A the His-tagged mutant remains highly active with tripolyphosphate as substrate and Mg2+ as activator, with a catalytic efficiency close to that of the recombinant wild type enzyme 719965 3.6.1.25 R265H no AdoMet synthetase activity, normal tripolyphosphatase activity 669193 3.6.1.25 R265S no AdoMet synthetase activity, reduced tripolyphosphatase activity 669193