Inhibition of Soybean Urease by Triketone Oximes

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E. I. Tarun, D. B. Rubinov, and D. I. Metelitza^*

Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, ul. Akademika Kuprevicha 5/2, 220141 Minsk, Belarus; fax: (375)-(172) 63-7274; E-mail: metelitza@iboch.bas-net.by

^* To whom correspondence should be addressed.

Received March 9, 2004; Revision received March 31, 2004

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Competitive inhibition of soybean urease by 15 triketone oximes has been studied at 36°C in aqueous solution (pH 4.95). The studied oximes are supposed chelators for the nickel atom in the urease metallocenter. The inhibition constants of urea hydrolysis (K_i) varied in the range 2.7-248 µM depending on the oxime structure. Analysis of this dependency demonstrates that the optimal inhibitor is the one containing carbonyl group in position 1 of the cycle, the ethoxyimino group and alkyl residue in the substituent in position 2, as well as the methoxycarbonyl group in position 4 of the cycle.

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KEY WORDS: soybean urease, inhibition, cyclic beta-triketones, triketone oximes, nickel chelators, inhibition mechanism

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