Purification and properties of the L-amino acid oxidase from monocellate cobra (Naja naja kaouthia) venom.
1. The L-amino acid oxidase of the monocellate cobra (Naja naja kaouthia) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 112,200 as determined by Sephadex G-200 gel filtration chromatography, and 57,400 as determined by SDS-polyacrylamide gel electrophoresis. 2. The enzyme had an isoelectric point of 8.12 and a pH optimum of 8.5. It showed remarkable thermal stability, and, unlike many venom L-amino acid oxidase, was also stable in alkaline medium. The enzyme was partially inactivated by freezing. 3. The enzyme was very active against L-phenylalanine and L-tyrosine, moderately active against L-tryptophan, L-methionine, L-leucine, L-norleucine, L-arginine and L-norvaline. Other L-amino acids were oxidized slowly or not oxidized. 4. Kinetic studies suggest the presence of a side-chain binding site in the enzyme, and that the binding site comprises of at least four hydrophobic subsites.
Tan
N H
NH
Department of Biochemistry, University of Malaya, Kuala Lumpur, Malaysia.
Swaminathan
S
S
D000594:Amino Acid Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004546:Elapid Venoms / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D050830:L-Amino Acid Oxidase; D010084:Oxidation-Reduction; D013379:Substrate Specificity
D000596:Amino Acids; D004546:Elapid Venoms; D000594:Amino Acid Oxidoreductases; D050830:L-Amino Acid Oxidase