[Spectrophotometric micromethod to determine L-lysine-alpha-oxidase activity]

A spectrophotometric micromethod is developed for estimation of L-lysine-alpha-oxidase. The method is based on measurement of hydrogen peroxide formed in enzymatic oxidation of L-lysine. Optimal conditions were developed for estimation of the enzymatic activity in the extracts of Trichoderma sp. The saturating concentration of L-lysine was 10 mM. Km values for L- and DL-lysines constituted 3.0 . 10(-3) M and 6.4 . 10(-4) M, respectively. The reaction proceeded without a latent phase and H2O2 formation versus time plot had a linear shape within 20 min. The enzyme optimal activity was found at pH 5.8-6.0. The best buffer, required for lysine oxidation in the reaction, proved to be phosphate, but not succinate, borate or glycine buffers. The method described was highly sensitive and reproducible.