engleski

Enzymatic activity of L-amino acid oxidase from snake venom Crotalus adamanteus in supercritical CO2

L-amino acid oxidase from snake venom Crotalus adamanteus was successfully tested as a catalyst in supercritical CO2 (SC-CO2). The enzyme activity was measured before and after exposure to supercritical conditions (40 °C, 110 bar). It was found that L-AAO activity increased after SC-CO2 exposure slightly up to 15 % in comparison to its initial value. Results showed that L-AAO is more stable in supercritical CO2 than in phosphate buffer under atmospheric pressure, as well as in the enzyme membrane reactor experiment. Enzyme reaction of 3, 4-Dihydroxyphenyl-L-alanine (L- DOPA) oxidation was performed in supercritical batch reactor made of stainless steel that could withstand the pressures of supercritical carbon dioxide. It was shown that L-amino acid oxidase from C. adamanteus is able to catalyse the reaction of oxidative deamination of L-DOPA in supercritical CO2. For the comparison L-DOPA oxidation was performed in the enzyme membrane reactor at 40 °C and pressure of 2.5 bar. Productivity expressed as mmol-s of converted L- DOPA after 3 hours per change of enzyme activity after 3 hours was the highest in supercritical CO2 (1.474 mmol U-1), where catalase was present, and the lowest in the enzyme membrane reactor (0.457 mmol U-1).

L-amino acid oxidase ; supercritical CO2 ; L-DOPA ; enzyme activity

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