3.2.2.6 D147A site-directed mutagenesis, the mutant shows a decrease in activity compared to the wild-type enzyme 731357 3.2.2.6 E138A site-directed mutagenesis, the mutation causes a modest increase in the rate of NAD+ transformation which is proportional to its concentration. At 4.0 M, the rate increase is about 1.2fold and the formation of beta-1'-O-methyl ADP-ribose amounts to about 80% of the total reaction products. The observed selectivity in favor of methanolysis is similar to that of wild-type enzyme. The ADP-ribosyl cyclase activity of E138A mutant is more affected by the competing nucleophile, i.e. formation of ADP-ribose and cADPR are reduced by 75% and 90% respectively at 4.0 M methanol, the mutant shows an increase in ADP cyclization and higly reduced overall activity compared to the wild-type enzyme 731357 3.2.2.6 E138Q site-directed mutagenesis, in the presence of methanol, mutant E138Q efficiently catalyzes the formation of beta-1'-O-methyl ADP-ribose. But in contrast with mutant E138A, and like the wild-type enzyme, solvolysis does not affect the overall turnover rate of NAD+ indicating that the formation of the E.ADP-ribosyl intermediate is still rate limiting 731357 3.2.2.6 E218A site-directed mutagenesis, the mutant shows a decrease in activity compared to the wild-type enzyme 731357 3.2.2.6 E218Q site-directed mutagenesis, catalytic site mutant, crystal structure analysis, almost inactive mutant 732691 3.2.2.6 E218Q site-directed mutagenesis, the mutant shows a decrease in activity compared to the wild-type enzyme 731357 3.2.2.6 E226D site-directed mutagenesis, catalytic mutant 731119 3.2.2.6 E226D site-directed mutagenesis, inactive catalytic site mutant 731987 3.2.2.6 E226Q site-directed mutagenesis, catalytic mutant 731119 3.2.2.6 E226Q site-directed mutagenesis, inactive catalytic site mutant 731987