A 1010 Rate Enhancement of Phosphodiester Hydrolysis by a Dinuclear Aminopeptidase—Transition-State Analogues as Substrates?

Streptomyces dizinc aminopeptidase (sAP) shows a specific activity of 33.7 nmol min(-1) mg(-1) toward the hydrolysis of the transition-state analogue bis-p-nitrophenylphosphate with a rate constant of k(cat)/K(m)=100 M(-1) s(-1) and a first-order rate enhancement of about 10(10), which is much superior to several Zn chemical models and comparable to some phosphodiesterases. This study suggests that sAP can serve as a novel dinuclear model system to provide further insight into dinuclear hydrolysis.