“ Mycophenolic acid … NAD+ , with a intercept inhibition constant (Kii) of 0.03 ± 0.004 μM. Tiazofurin and its seleno analog were not inhibitory to the purified … nonhydrolyzable β-methylene derivatives of TAD or SAD were inhibitory, with Kii values 13- to 60-fold higher than that of mycophenolic acid.”