Remarkable Enhancement of the Hydrolyses of Phosphoesters by Dimetal Centers
—Streptomyces Aminopeptidase as a "Natural Model System"

Altan Ercan, Hyun Ik Park, and Li-June Ming*

Department of Chemistry and
Institute for Biomolecular Science
University of South Florida
Tampa, Florida 33620-5250

Abstract

Although tetrahedral phospho-containing compounds often serve as transition-state inhibitors for proteases, bis(p-nitrophenyl)phosphate and p-nitrophenyl phenylphosphonate were found to be very effectively hydrolyzed by the dinuclear aminopeptidase from Streptomyces griseus (sAP) and its Co²⁺, Ni²⁺, Mn²⁺, and Cd²⁺ derivatives with high catalytic proficiencies (0.94–67 billion and 0.043–0.29 million, respectively, relative to auto-hydrolytic) and specific activities comparable to those of some phosphoesterases. However, hydrolyses of a phosphomonoester and two phosphotriesters are not detected under the same conditions. The versatile hydrolytic activities of sAP and derivatives suggest that they can serve as novel dinuclear "natural model systems" to provide further insight into dinuclear hydrolysis in chemical and biological systems.

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