Inhibition of Solubilized Superoxide Dismutase Co-immobilized with Catalase by the Polydisulfide of Gallic Acid

A. N. Eryomin,¹ Yu. P. Losev,² and D. I. Metelitza^1,3

¹Institute of Bioorganic Chemistry, Academy of Sciences of Belarus, ul. Zhodinskaya 5/2, Minsk, 220141 Belarus; fax: (0172) 63-72-74; E-mail: ibochbel@eco2.iasnet.com

²School of Chemistry, Belarus State University, ul. Leningradskaya 14, Minsk, 220080 Belarus; fax: (0172) 26-59-42.

³To whom correspondence should be addressed.

Submitted February 13, 1997; revision submitted April 17, 1997.

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The catalytic activity of superoxide dismutase (SOD) and its conjugates with catalase and polymer peroxidase (p-peroxidase) obtained during covalent binding of enzymes with aldehyde dextrans was indirectly characterized by inhibition of adrenaline autoxidation in 0.1 M bicarbonate buffer, pH 10.2, and in microemulsion of 0.1 M aerosol OT (AOT) and Triton X-45 in octane containing 15% aqueous phase. The polydisulfide of gallic acid (PDGA) effectively inhibited SOD and its conjugates by a mixed mechanism. The inhibition constants K_i for SOD and its conjugate (SOD--catalase)_mic in 0.1 M bicarbonate buffer, pH 10.2, were 0.1 and 0.25 µM, respectively. Autoxidation of PDGA by molecular oxygen in alkaline media (pH 10.2) influenced its inhibitory properties in buffer solution and microemulsion of AOT and Triton X-45 in octane. The radical chain mechanism of co-oxidation of adrenaline and PDGA apparently includes the anion radical O₂^· as a coupling agent which propagated the chain.

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KEY WORDS: superoxide dismutase, co-immobilized superoxide dismutase and catalase, bioantioxidant, polydisulfide of gallic acid, inhibition of antioxidant enzyme, co-oxidation of adrenaline and polydisulfide of gallic acid.

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