The selective inhibition of phosphatases by natural toxins: the anhydride domain of tautomycin is not a primary factor in controlling PP1/PP2A selectivity

Analogues of the potent and moderately selective PP1/PP2A inhibitor tautomycin (TM) were prepared with modifications in the C1'-C7' anhydride moiety. While all retain varying degrees of activity within a 3000-fold range of potencies, they also show remarkable constancy in their IC(50) ratios, suggesting that the anhydride moiety is not critical in controlling the selectivity of inhibition.