Aryl sulfatase from Naja nigricolis venom: characterization and possible contribution in the pathology of snake poisoning.
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 degrees C. Arrhenius plot for the determination of the activation energy (E(a)) gave the value 25 kJ/mol with a half-life (t(1/2)) of 5 min at 50 degrees C. It was highly activated by Fe(2+) and Ca(2+) and inhibited by Co(2+) and Mn(2+). The enzyme catalyzed the hydrolysis of the fluorescent compound methylumbelliferyl-sulfate (MU-SO(4)). Double reciprocal plots of initial velocity data, using MU-SO(4) as substrate, gave a K(M) value of 110 microM and V(max) of 225 micromol min(-1) x mg(-1). N. nigricolis Aryl sulphatase also hydrolyzed chondroitin-4-sulphate. It was inhibited competitively by N-acetyl glucosamine sulfate (GlcNAc-SO(4)), glucose-6-sulfate (Glc-6-SO(4)), and glucose 1-sulfate (Glc-1-SO(4)). Extrapolated inhibition binding constants (K(i)) gave the values of 3, 25, and 315 microM for GlcNAc-SO(4), Glc-6-SO(4), and Glc-1-SO(4) respectively.
Nok
Andrew J
AJ
Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria.
Abubakar
M S
MS
Adaudi
Ambrose
A
Balogun
E
E
D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001192:Arylsulfatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002413:Cations, Divalent / Q000494:pharmacology; D002809:Chondroitin Sulfates / Q000378:metabolism; D004546:Elapid Venoms / Q000201:enzymology* / Q000506:poisoning; D005947:Glucose / Q000031:analogs & derivatives / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006923:Hymecromone / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D011485:Protein Binding; D013379:Substrate Specificity; D013696:Temperature; D013816:Thermodynamics
D002413:Cations, Divalent; D004546:Elapid Venoms; C019492:4-methylumbelliferyl sulfate; D006923:Hymecromone; D002809:Chondroitin Sulfates; D001192:Arylsulfatases; D005947:Glucose; D000117:Acetylglucosamine