Purification and properties of the L-amino acid oxidase from monocellate cobra (Naja naja kaouthia) venom

Int J Biochem. 1992 Jun;24(6):967-73. doi: 10.1016/0020-711x(92)90105-a.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Oxidoreductases / isolation & purification
  • Amino Acid Oxidoreductases / metabolism*
  • Amino Acids / metabolism
  • Chromatography, Gel
  • Chromatography, Ion Exchange
  • Elapid Venoms / enzymology*
  • Hydrogen-Ion Concentration
  • Kinetics
  • L-Amino Acid Oxidase
  • Oxidation-Reduction
  • Substrate Specificity


  • Amino Acids
  • Elapid Venoms
  • Amino Acid Oxidoreductases
  • L-Amino Acid Oxidase