Aryl sulfatase from Naja nigricolis venom: Characterization and possible contribution in the pathology of snake poisoning

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Abstract

The venom of Naja nigricolis was found to contain a high level of the enzyme aryl sulfatase. The enzyme was isolated from the venom of N. nigriclois and purified to electrophoretic homogeneity by gel chromatography on Sephadex G-100, DEAE-cellulose, and phenyl-sepharose columns. The enzyme was optimally active at pH 5 and 40°C. Arrhenius plot for the determination of the activation energy (Ea) gave the value 25 kJ/mol with a half-life (t1/2) of 5 min at 50°C. It was highly activated by Fe2+ and Ca2+ and inhibited by Co2+ and Mn2+. The enzyme catalyzed the hydrolysis of the fluorescent compound methylumbelliferyl-sulfate (MU-SO4). Double reciprocal plots of initial velocity data, using MU-SO4 as substrate, gave a KM value of 110 μM and Vmax of 225 μmol min−1 mg−1. N. nigricolis Aryl sulphatase also hydrolyzed chondroitin-4-sulphate. It was inhibited competitively by N-acetyl glucosamine sulfate (GlcNAc-SO4), glucose-6-sulfate (Glc-6-SO4), and glucose 1-sulfate (Glc-1-SO4). Extrapolated inhibition binding constants (Ki) gave the values of 3, 25, and 315 μM for GlcNAc-SO4, Glc-6-SO4, and Glc-1-SO4 respectively. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:59–66, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10061

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